Transcription complète de Chapter 3

00:04:42.279 and foot of a small bird with a hind toe 63 00:04:42.319 --> 00:04:46.319 cut off. The straight leg or tarsus, is longer than 64 00:04:46.319 --> 00:04:49.319 the three toes, which are of equal length and diverging 65 00:04:49.720 --> 00:04:53.560 lie in the same plane. The toes terminate in sharp, 66 00:04:53.600 --> 00:04:57.480 hard claws, much curved downwards, like those on a bird's foot. 67 00:04:58.240 --> 00:05:01.759 The petiole of the leaf is sent to contact. Even 68 00:05:01.800 --> 00:05:04.720 a small loop of thread suspended for two days caused 69 00:05:04.720 --> 00:05:08.000 it to bend upwards. But the subpediles of the two 70 00:05:08.240 --> 00:05:12.920 lateral leaflets are not sensitive. The whole tendril, namely the tarsus, 71 00:05:12.959 --> 00:05:16.680 and the three toes are likewise sensitive to contact, especially 72 00:05:16.720 --> 00:05:20.040 on their under surfaces. When a shoot grows in the 73 00:05:20.079 --> 00:05:23.360 midst of thin branches, the tendrils are soon brought by 74 00:05:23.399 --> 00:05:26.959 the revolving movement of the internodes into contact with them, 75 00:05:27.360 --> 00:05:30.319 and then one toe of the tendril, or more commonly 76 00:05:30.360 --> 00:05:34.279 all three, bend and after several hours seese a fast 77 00:05:34.319 --> 00:05:38.199 hold of the twigs like a bird when perched. If 78 00:05:38.199 --> 00:05:40.959 the tarsus of the tendril comes into contact with a twig, 79 00:05:41.319 --> 00:05:44.079 it goes on slowly bending until the whole foot is 80 00:05:44.120 --> 00:05:47.399 carried quite round, and the toe passes on each side 81 00:05:47.399 --> 00:05:50.839 of the tarsus and seas it in like manner. If 82 00:05:50.839 --> 00:05:54.199 the petile comes into contact with a twig, it bends round, 83 00:05:54.360 --> 00:05:57.800 carrying the tendril, which then seizes its own petiole or 84 00:05:57.839 --> 00:06:02.199 that of the opposite leaf. The petioles move spontaneously, and 85 00:06:02.279 --> 00:06:05.560 thus when a shoot attempts to twine round an upright stick, 86 00:06:05.959 --> 00:06:09.040 those on both sides. After a time come into contact 87 00:06:09.120 --> 00:06:12.600 with it and are excited to bend. Ultimately, the two 88 00:06:12.680 --> 00:06:16.360 petioles clasp the stick in opposite directions, and the foot 89 00:06:16.480 --> 00:06:20.480 like tendrils, seizing on each other or on their own petioles, 90 00:06:20.759 --> 00:06:25.120 fasten the stem to the support with surprising security. The 91 00:06:25.199 --> 00:06:28.360 tendrils are thus brought into action if the stem twines 92 00:06:28.480 --> 00:06:31.639 round a thin vertical stick, and in this respect the 93 00:06:31.680 --> 00:06:36.240 present species differs from the last. Both species use their 94 00:06:36.279 --> 00:06:39.199 tendrils in the same manner when passing through a thicket. 95 00:06:39.839 --> 00:06:42.879 This plant is one of the most efficient climbers

which 96 00:06:42.879 --> 00:06:46.240 I have observed, and it probably could ascend a polished 97 00:06:46.279 --> 00:06:50.759 stem incessantly tossed by heavy storms. To show how important 98 00:06:50.920 --> 00:06:53.680 vigorous health is for the action of all the parts, 99 00:06:54.040 --> 00:06:56.560 I may mention that when I first examined a plant 100 00:06:56.600 --> 00:07:00.600 which was growing moderately well, though not vigorously, I concluded 101 00:07:00.639 --> 00:07:03.959 that the tendrils acted only like the hooks on a bramble, 102 00:07:04.040 --> 00:07:06.519 and that it was a most feeble and inefficient of 103 00:07:06.560 --> 00:07:12.240 all climbers. Bignonia twidiana. This species is closely allied to 104 00:07:12.279 --> 00:07:14.879 the last and behaves in the same manner, but perhaps 105 00:07:14.959 --> 00:07:19.360 twines rather better round a vertical stick. On the same plant, 106 00:07:19.519 --> 00:07:22.439 one branch twined in one direction and another in an 107 00:07:22.480 --> 00:07:26.720 opposite direction. The internodes in one case made two circles 108 00:07:26.759 --> 00:07:30.120 each in two hours thirty three minutes. I was enabled 109 00:07:30.160 --> 00:07:33.199 to observe the spontaneous movements of the petioles better in 110 00:07:33.279 --> 00:07:37.560 this than in the preceding two species. One petiole described 111 00:07:37.600 --> 00:07:40.720 three small vertical ellipses in the course of eleven hours, 112 00:07:41.040 --> 00:07:45.600 whilst another moved in an irregular spire. Some little time 113 00:07:45.720 --> 00:07:48.639 after a stem has twined round an upright stick and 114 00:07:48.800 --> 00:07:52.120 is securely fastened to it by the clasping petioles and tendrils, 115 00:07:52.399 --> 00:07:55.439 it emits aerial roots from the bases of its leaves, 116 00:07:55.480 --> 00:07:59.079 and these roots curve partly round and adhere to the stick. 117 00:07:59.839 --> 00:08:04.079 The species of Bignonia therefore combines four different methods of climbing, 118 00:08:04.399 --> 00:08:10.000 generally characteristic of distinct plants, namely twining, leaf climbing, tendril climbing, 119 00:08:10.079 --> 00:08:13.959 and root climbing. In the three foregoing species, when the 120 00:08:13.959 --> 00:08:17.120 foot like tendril has caught an object, it continues to 121 00:08:17.160 --> 00:08:20.920 grow and thicken and ultimately becomes wonderfully strong. In the 122 00:08:20.959 --> 00:08:24.279 same manner as the pediles of leaf climbers. If the 123 00:08:24.319 --> 00:08:27.879 tendril catches nothing, it first slowly bends downwards, and then 124 00:08:27.920 --> 00:08:31.759 its power of clasping is lost. Very soon afterwards, it 125 00:08:32.320 --> 00:08:35.120 articulates itself from the pediole and drops off like a 126 00:08:35.200 --> 00:08:38.080 leaf in autumn. I have seen that this process of 127 00:08:38.120 --> 00:08:42.120 derse articulation in no other tendrils, for

these, when they 128 00:08:42.120 --> 00:08:47.000 fail to catch an object, merely wither away. Bignonia venusta. 129 00:08:47.720 --> 00:08:51.200 The tendrils differ considerably from those of the previous species. 130 00:08:51.639 --> 00:08:54.480 The lower part, or tarsus, is four times as long 131 00:08:54.559 --> 00:08:57.519 as the three toes. These are of equal length and 132 00:08:57.639 --> 00:09:00.440 diverge equally, but do not lie in the same plane. 133 00:09:01.159 --> 00:09:03.919 Their tips are bluntly hooked, and the whole tendril makes 134 00:09:03.960 --> 00:09:08.320 an excellent grapnel. The tarsus is sensitive on all sides, 135 00:09:08.480 --> 00:09:11.799 but the three toes are sensitive only on their outer surfaces. 136 00:09:12.480 --> 00:09:15.720 The sensitiveness is not much developed. For A slight rubbing 137 00:09:15.759 --> 00:09:18.080 with the twig did not cause the tarsus or the 138 00:09:18.159 --> 00:09:21.759 toes to become curved until an hour had elapsed, and 139 00:09:21.840 --> 00:09:26.159 then only in a slight degree. Subsequently, they straightened themselves. 140 00:09:26.720 --> 00:09:29.879 Both the tarsus and toes can seize well hold of sticks. 141 00:09:30.240 --> 00:09:34.240 If the stem is secured, The tendrils are seen spontaneously 142 00:09:34.320 --> 00:09:38.519 to sweep large ellipses, the two opposite tendrils moving independently 143 00:09:38.559 --> 00:09:41.840 of one another. I have no doubt from the analogy 144 00:09:41.879 --> 00:09:45.720 of the two form following allied species, that the petioles 145 00:09:45.759 --> 00:09:49.519 also move spontaneously, but they are not irritable like those 146 00:09:49.600 --> 00:09:54.080 of B. Ungliss and B. Tridiana. The young internodes sweep 147 00:09:54.200 --> 00:09:57.440 large circles, one being completed in two hours fifteen minutes 148 00:09:57.480 --> 00:10:00.720 and a second in two hours fifty five minutes. By 149 00:10:00.799 --> 00:10:04.080 these combined movements of the internodes of petioles and grapnel 150 00:10:04.159 --> 00:10:07.440 leg tendrils, the latter are soon brought into contact with 151 00:10:07.480 --> 00:10:11.559 surrounding objects. When a choote stands near an upright stick, 152 00:10:11.879 --> 00:10:15.840 it twines regularly and spirally round it. As it ascends, 153 00:10:15.879 --> 00:10:18.360 it ceases the stick with one of its tendrils, and 154 00:10:18.639 --> 00:10:21.440 if the stick be thin, the right and left hand 155 00:10:21.559 --> 00:10:26.279 tendrils are alternately used. This alternation follows from the stem 156 00:10:26.399 --> 00:10:29.919 necessarily taking one twist round its own axis for each 157 00:10:30.000 --> 00:10:35.480 completed circle. The tendril's contract spirally a short time after 158 00:10:35.559 --> 00:10:40.399 catching any object those which catch nothing nearly bend slowly downwards. 159 00:10:40.679 --> 00:10:43.480 But the whole subject of the spiral contraction

of the 160 00:10:43.519 --> 00:10:47.559 tendrils will be discussed after all. The tendril bearing species 161 00:10:47.600 --> 00:10:53.360 have been described. Bignonia littoralis. The young internodes revolved in 162 00:10:53.480 --> 00:10:58.039 large ellipses. An internode bearing immature tendrils made two revolutions 163 00:10:58.080 --> 00:11:01.399 each in three hours fifty minutes, but when grown older, 164 00:11:01.440 --> 00:11:04.919 with the tendrils mature, it made two ellipses each at 165 00:11:05.000 --> 00:11:08.399 the rate of two hours forty four minutes. This species, 166 00:11:08.559 --> 00:11:11.519 unlike the preceding, is incapable of twining round a stick. 167 00:11:12.120 --> 00:11:14.080 It does not appear to be due to any want 168 00:11:14.159 --> 00:11:16.879 of flexibility in the internodes, or to the action of 169 00:11:16.879 --> 00:11:19.720 the tendrils, and certainly not to any want of the 170 00:11:19.759 --> 00:11:24.840 revolving power. Nor can I account for the fact. Nevertheless, 171 00:11:24.879 --> 00:11:28.519 the plant readily ascends a thin upright stick by seizing 172 00:11:28.559 --> 00:11:32.039 a point above it with its two opposite tendrils, which 173 00:11:32.080 --> 00:11:36.000 then contract spirally. If the tendril sees nothing, they do 174 00:11:36.039 --> 00:11:40.440 not become spiral. The species last described ascended a vertical 175 00:11:40.440 --> 00:11:44.279 stick by twining spirally and by seizing it alternately with 176 00:11:44.399 --> 00:11:47.720 its opposite tendrils. Like a sailor pulling himself up a 177 00:11:47.799 --> 00:11:51.919 rope hand over hand. The present species pulls itself up 178 00:11:52.000 --> 00:11:55.240 like a sailor seizing with both hands together a rope 179 00:11:55.320 --> 00:11:59.039 above his head. The tendrils are similar in structure to 180 00:11:59.039 --> 00:12:02.120 those of the last species. They continue growing for some 181 00:12:02.200 --> 00:12:06.039 time even after they have clasped an object. When fully grown, 182 00:12:06.200 --> 00:12:09.039 though borne by a young plant, they are nine inches 183 00:12:09.080 --> 00:12:13.919 in length. The three divergent toes are shorter relatively to 184 00:12:14.039 --> 00:12:17.720 the tarsus than in the former species. They are blocked 185 00:12:17.720 --> 00:12:20.799 at their tips and but slightly hooked. They are not 186 00:12:20.879 --> 00:12:23.960 quite equal in length, the middle one being rather longer 187 00:12:24.000 --> 00:12:28.440 than the others. Their outer surfaces are highly sensitive, for 188 00:12:28.480 --> 00:12:31.720 when lightly rubbed with a twig, they become perceptibly curved 189 00:12:31.759 --> 00:12:35.519 in four minutes and greatly curved in seven minutes. In 190 00:12:35.600 --> 00:12:39.240 seven hours, they became straight again and were ready to react. 191 00:12:40.120 --> 00:12:42.600 The tarsus, for the space of one inch close to 192 00:12:42.600 --> 00:12:45.720 the toes, is sensitive, but in a rather less degree 193 00:12:45.759 --> 00:12:48.679 than the toes. For the latter, after a slight rubbing, 194 00:12:48.720 --> 00:12:52.399 became curved in about half the time. Even the middle 195 00:12:52.440 --> 00:12:55.879 part of the tarsus is sensitive to prolonged contact. As 196 00:12:55.919 --> 00:12:59.519 soon as the tendril has arrived at maturity. After it 197 00:12:59.559 --> 00:13:02.440 has grown, all the sensitiveness is confined to the toes, 198 00:13:02.679 --> 00:13:05.679 and these are only able to curl very slowly round 199 00:13:05.679 --> 00:13:09.279 a stick. A tendril is perfectly ready to act as 200 00:13:09.320 --> 00:13:12.039 soon as the three toes have diverged, and at this 201 00:13:12.159 --> 00:13:17.039 period their outer surfaces first become irritable. The irritability spreads 202 00:13:17.080 --> 00:13:20.240 but little from one part when excited to another. Thus, 203 00:13:20.320 --> 00:13:23.039 when a stick was caught by the part immediately beneath 204 00:13:23.200 --> 00:13:27.039 the three toes, these seldom clasped it, but remained sticking 205 00:13:27.159 --> 00:13:32.799 straight aft. The tendrils revolve spontaneously. The movement begins before 206 00:13:32.799 --> 00:13:35.759 the tendril is converted into a three pronged grapnel by 207 00:13:35.799 --> 00:13:38.679 the divergence of the toes, and before any part has 208 00:13:38.720 --> 00:13:42.399 become sensitive, so that the revolving movement is useless at 209 00:13:42.399 --> 00:13:46.559 this early period. The movement is also now slow, to 210 00:13:46.639 --> 00:13:50.519 ellipses being completed conjointly in twenty four hours eighteen minutes. 211 00:13:51.120 --> 00:13:54.200 A mature tendril made an ellipse in six hours, so 212 00:13:54.240 --> 00:13:58.039 that moved much more slowly than the internodes. The ellipses, 213 00:13:58.080 --> 00:14:01.000 which were swept both in a vertical and horizontal plane 214 00:14:01.039 --> 00:14:04.000 were of large size. The petioles are not in the 215 00:14:04.080 --> 00:14:08.039 least sensitive, but revolve like the tendrils. We thus see 216 00:14:08.159 --> 00:14:11.759 that the young internodes, the petioles, and the tendrils all 217 00:14:11.799 --> 00:14:16.440 continue revolving together, but at different rates. The movements of 218 00:14:16.519 --> 00:14:21.039 the tendrils, which rise opposite one another, are quite independent. Hence, 219 00:14:21.080 --> 00:14:23.960 when the whole shoot is allowed freely to revolve, nothing 220 00:14:24.000 --> 00:14:26.960 can be more intricate than the course followed by the 221 00:14:27.000 --> 00:14:31.279 extremity of each tendril. A wide space is thus irregularly 222 00:14:31.320 --> 00:14:36.080 searched for some object to be grasped. One other curious 223 00:14:36.120 --> 00:14:39.440 point remains to be mentioned. In the course of a 224 00:14:39.480 --> 00:14:42.559 few days, after the toes

have closely clasped a stick, 225 00:14:42.919 --> 00:14:47.360 their blunt extremities become developed, though not invariably, into irregular 226 00:14:47.399 --> 00:14:50.600 disc like balls, which have the power of adhering firmly 227 00:14:50.639 --> 00:14:54.759 to the wood. As similar cellular outgrowths will be fully 228 00:14:54.799 --> 00:14:58.799 described under the caprilata, I will hear say nothing more 229 00:14:58.799 --> 00:15:07.879 about them. Bignonia equinoctalis variation in Chamberlayne. The internodes, the elongated, 230 00:15:08.080 --> 00:15:12.039 non sensitive petiles, and the tendrils all revolve. The stem 231 00:15:12.080 --> 00:15:14.279 does not twine, but ascends a vertical stick in the 232 00:15:14.320 --> 00:15:18.000 same manner as the last species. The tendrils also resemble 233 00:15:18.120 --> 00:15:21.159 those of the last species, but are shorter. The three 234 00:15:21.240 --> 00:15:24.159 toes are more unequal in length, the two outer ones 235 00:15:24.240 --> 00:15:26.600 being about one third shorter and rather thinner than the 236 00:15:26.639 --> 00:15:30.639 middle toe, but they vary in this respect. They terminate 237 00:15:30.720 --> 00:15:34.679 in small hard points, and of what is important, cellular 238 00:15:34.759 --> 00:15:38.960 adhesive discs are not developed. The reduced size of the 239 00:15:39.000 --> 00:15:42.399 two toes, as well as their lessened sensitiveness, seem to 240 00:15:42.399 --> 00:15:45.919 indicate a tendency to abortion, and on one of my plants, 241 00:15:45.919 --> 00:15:49.600 the first formed tendrils were sometimes simple, that is, not 242 00:15:49.679 --> 00:15:53.440 divided into three toes. We are thus naturally led to 243 00:15:53.519 --> 00:16:00.120 the three following species with undivided tendrils. Bignonia speciosa. The 244 00:16:00.159 --> 00:16:04.720 young shoots revolve irregularly, making narrow lipses, spires, or circles 245 00:16:05.000 --> 00:16:07.679 at rates varying from three hour thirty minutes to four 246 00:16:07.720 --> 00:16:11.480 hour forty minutes, but they show no tendance each twine. 247 00:16:11.960 --> 00:16:14.840 Whilst the plant is young and does not require a support, 248 00:16:14.960 --> 00:16:18.360 tendrils are not developed. Those borne by a moderately young 249 00:16:18.440 --> 00:16:22.679 plant were five inches in length. They revolve spontaneously, as 250 00:16:22.759 --> 00:16:26.320 do the short and non sensitive petules, when rubbed facially, 251 00:16:26.360 --> 00:16:29.360 bend to the rub side and subsequently straighten themselves, but 252 00:16:29.519 --> 00:16:33.000 they are not highly sensitive. There is something strange in 253 00:16:33.039 --> 00:16:37.440 their behavior. I repeatedly placed close to them thick and thin, 254 00:16:37.799 --> 00:16:40.759 rough and smooth sticks and posts, as well as the 255 00:16:40.759 --> 00:16:44.320 string suspended vertically, but none of the objects were well seized.

256 00:16:44.759 --> 00:16:48.320 After clasping an upright stick, they repeatedly loosed it again 257 00:16:48.559 --> 00:16:51.399 and often would not seize it at all, or their 258 00:16:51.440 --> 00:16:55.799 extremities did not coil closely round. I have observed hundreds 259 00:16:55.799 --> 00:17:01.679 of tendrils belonging to very concurbidaceous, passifloracious and Lugamenos plants, 260 00:17:01.759 --> 00:17:06.160 and have never saw one behave in this manner. When, however, 261 00:17:06.240 --> 00:17:08.160 my plant had grown to a height of eight or 262 00:17:08.240 --> 00:17:12.200 nine feet, the tendrils acted much better. They now seized 263 00:17:12.240 --> 00:17:15.400 a thin upright stick horizontally, that is, at a point 264 00:17:15.480 --> 00:17:17.759 on their own level, and not some way up the stick, 265 00:17:17.839 --> 00:17:21.319 as in the case of all the previous species. Nevertheless, 266 00:17:21.319 --> 00:17:24.400 the non twining stem was enabled by these means to 267 00:17:24.440 --> 00:17:28.759 ascend the stick. The extremity of the tendril is almost 268 00:17:28.920 --> 00:17:33.240 straight and sharp. The whole terminal portion exhibits a singular habit, 269 00:17:33.359 --> 00:17:36.119 which in an animal would be called an instinct, for 270 00:17:36.200 --> 00:17:39.359 it continually searches for any little crevice or hole into 271 00:17:39.359 --> 00:17:43.319 which to insert itself. I had two young plants, and 272 00:17:43.400 --> 00:17:46.720 after having observed this habit, I placed them near posts 273 00:17:46.960 --> 00:17:49.720 which have been bored by beetles or have become fissured 274 00:17:49.759 --> 00:17:53.160 by drying. The tendrils, by their own movement and by 275 00:17:53.200 --> 00:17:56.319 that of the internodes, slowly traveled over the surface of 276 00:17:56.319 --> 00:17:58.720 the wood, and when the apex came to a hole 277 00:17:58.839 --> 00:18:03.279 or fissure, it aserted itself. In order to effect this extremity, 278 00:18:03.759 --> 00:18:06.720 for a length of half or quarter of an inch, 279 00:18:06.960 --> 00:18:10.200 would often bend itself at right angles to the basal part. 280 00:18:11.079 --> 00:18:14.279 I have watched this process between twenty and thirty times. 281 00:18:14.680 --> 00:18:17.559 The same tendril would frequently withdraw from one hole and 282 00:18:17.680 --> 00:18:20.920 insert its point into a second hole. I have also 283 00:18:20.960 --> 00:18:23.359 seen a tendril keep its point in one case for 284 00:18:23.440 --> 00:18:26.400 twenty hours and in another for thirty six hours in 285 00:18:26.440 --> 00:18:30.519 a minute hole, and then withdraw it. Whilst the point 286 00:18:30.559 --> 00:18:34.480 is thus temporarily inserted, the opposite tendril goes on revolving 287 00:18:35.960 --> 00:18:39.240 the whole length of a tendril often fits itself closely 288 00:18:39.279 --> 00:18:41.759 to any surface of wood with which it has come 289 00:18:41.799 --> 00:18:45.000 into contact, and I have observed one bent at right 290 00:18:45.039 --> 00:18:48.720 angles from having entered a wide and deep fissure, with 291 00:18:48.799 --> 00:18:53.359 its apex abruptly rebent and inserted into a minute lateral hole. 292 00:18:54.160 --> 00:18:57.680 After a tendril has clasped a stick, it contracts spirally 293 00:18:58.240 --> 00:19:02.359 if it remains unattached its straight downwards, if it has 294 00:19:02.400 --> 00:19:05.440 merely adapted itself to the inequalities of a thick post 295 00:19:05.519 --> 00:19:08.839 though it has clasped nothing, or if it has inserted 296 00:19:08.880 --> 00:19:12.759 its apex into some little fissure, the stimulus suffices to 297 00:19:12.839 --> 00:19:16.799 induce spiral contraction. But the contraction always draws the tendril 298 00:19:16.880 --> 00:19:20.559 away from the post, so that in every case these movements, 299 00:19:20.759 --> 00:19:24.519 which seem so nicely adapted for some purpose, were useless. 300 00:19:25.200 --> 00:19:28.559 On one occasion, however, the tip became permanently jammed into 301 00:19:28.559 --> 00:19:32.440 a narrow fissure. I fully expected from the analogy of B. 302 00:19:32.839 --> 00:19:36.799 Caprolata and B. Littoralis that the tips would have been 303 00:19:36.920 --> 00:19:40.759 developed into adhesive disks, but I could never detect even 304 00:19:40.799 --> 00:19:44.240 a trace of this process. There is, therefore, at present 305 00:19:44.319 --> 00:19:49.920 something unintelligible about the habits of this plant, Bignonia pictup. 306 00:19:50.480 --> 00:19:53.839 The species closely resembles the last in the structured movement 307 00:19:53.880 --> 00:19:57.720 of its tendrils. I also casually examined a fine growing 308 00:19:57.759 --> 00:20:01.720 plant of the allied B. Lindl lay, and this apparently 309 00:20:01.759 --> 00:20:06.599 behaved in all respects in the same manner Bignonia capriolata. 310 00:20:07.319 --> 00:20:09.680 We now come to a species having tendrils of a 311 00:20:09.720 --> 00:20:13.599 different type, but first for the internodes. A young shoot 312 00:20:13.680 --> 00:20:17.119 made three large revolutions following the sun at an average 313 00:20:17.200 --> 00:20:19.920 rate of two hours twenty three minutes. The stem is 314 00:20:19.960 --> 00:20:22.559 thin and flexible, and I have seen one make four 315 00:20:22.680 --> 00:20:26.759 regular spiral turns round a thin upright stick, ascending of 316 00:20:26.799 --> 00:20:30.240 course from right to left, and therefore in a reversed 317 00:20:30.359 --> 00:20:34.799 direction compared with the before described species. Afterwards, from the 318 00:20:34.839 --> 00:20:37.960 interference of the tendrils, it ascended either straight up to 319 00:20:38.039 --> 00:20:42.200 stick or in an irregular spire. The tendrils are, in 320 00:20:42.240 --> 00:20:45.680 some respects highly remarkable. In a young plant, they were 321

00:20:45.720 --> 00:20:48.279 about two and a half inches in length and much branched. 322 00:20:48.640 --> 00:20:52.319 The five chief branches apparently representing two pairs of leaflets 323 00:20:52.359 --> 00:20:56.359 and a terminal one. Each branch is, however, bifit or 324 00:20:56.440 --> 00:21:00.519 more commonly trifed towards the extremity, with the points blunt 325 00:21:00.599 --> 00:21:04.440 yet distinctly hooked. A tendril bends to any side which 326 00:21:04.519 --> 00:21:08.000 is lightly rubbed, and subsequently comes straight again. But a 327 00:21:08.039 --> 00:21:11.119 loop of thread weighing one fourth of a grain produced 328 00:21:11.240 --> 00:21:15.519 no effect. On two occasions, the terminal branches became slightly 329 00:21:15.559 --> 00:21:18.119 curved in ten minutes after they had touched a stick, 330 00:21:18.480 --> 00:21:21.079 and in thirty minutes the tips were curled quite round it. 331 00:21:21.720 --> 00:21:25.039 The basal part is less sensitive. The tendrils revolved in 332 00:21:25.079 --> 00:21:29.160 their apparently capricious manner, sometimes very slightly or not at all. 333 00:21:29.480 --> 00:21:33.480 At other times they described large, regular ellipses. I could 334 00:21:33.480 --> 00:21:37.079 detect no spontaneous movement in the petioles of the leaves. 335 00:21:37.559 --> 00:21:41.240 Whilst the tendrils are revolving more or less regularly, another 336 00:21:41.319 --> 00:21:45.119 remarkable movement takes place, namely, a slow inclination from the 337 00:21:45.240 --> 00:21:48.640 light towards the darkest side of the house. I repeatedly 338 00:21:48.720 --> 00:21:51.519 changed the position of my plants, and some little time 339 00:21:51.559 --> 00:21:55.240 after the revolving movement had ceased, the successively formed tendrils 340 00:21:55.279 --> 00:21:58.920 always ended by pointing to the darkest side. When I 341 00:21:58.960 --> 00:22:01.480 placed a thick post near a tendril between it and 342 00:22:01.519 --> 00:22:06.000 the light. The tendril pointed in that direction. In two instances, 343 00:22:06.039 --> 00:22:08.799 a pair of leaves stood so that one of the 344 00:22:08.799 --> 00:22:11.319 two tendrils was directed towards the light, and the other 345 00:22:11.400 --> 00:22:14.079 to the darkest side of the house. The latter did 346 00:22:14.119 --> 00:22:17.240 not move, but the opposite one mend itself first upwards 347 00:22:17.519 --> 00:22:20.039 and then right over its fellow, so that the two 348 00:22:20.119 --> 00:22:23.359 became parallel, one above the other, both pointing to the 349 00:22:23.440 --> 00:22:26.960 dark I then turned the plant round, and the tendril, 350 00:22:27.000 --> 00:22:30.079 which had turned over, recovered its original position, and the 351 00:22:30.119 --> 00:22:33.400 opposite one, which had not before moved, now turned over 352 00:22:33.440 --> 00:22:37.359 to the dark side. Lastly, on another plant, three pairs 353 00:22:37.359 --> 00:22:40.480 of tendrils were produced at the same time by three shoots, 354 00:22:40.720 --> 00:22:44.039 and all happened to be differently directed. I placed the 355 00:22:44.039 --> 00:22:46.799 pot in a box, open only on one side and 356 00:22:46.839 --> 00:22:50.559 obliquely facing the light. In two days, all six tendrils 357 00:22:50.559 --> 00:22:54.119 pointed with unerring truth to the darkest corner of the box. 358 00:22:54.440 --> 00:22:56.480 Though to do this each had to bend in a 359 00:22:56.519 --> 00:23:00.400 different manner. Six wind vanes could not have more truly 360 00:23:00.519 --> 00:23:03.400 shown the direction of the wind. Then did these branched 361 00:23:03.519 --> 00:23:06.440 tendrils the course of the stream of light which entered 362 00:23:06.440 --> 00:23:10.240 the box. I left these tendrils undisturbed for above twenty 363 00:23:10.279 --> 00:23:13.480 four hours, and then turned the pot half round. But 364 00:23:13.759 --> 00:23:16.279 they had now lost their power of movement and could 365 00:23:16.319 --> 00:23:19.839 no longer avoid the light. When a tendril has not 366 00:23:19.960 --> 00:23:23.279 succeeded in clasping the support, either through its own revolving 367 00:23:23.359 --> 00:23:26.079 movement or that of the shoot, or by turning towards 368 00:23:26.119 --> 00:23:29.960 any object which intercepts the light, it bends vertically downwards, 369 00:23:29.960 --> 00:23:33.079 and then towards its own stem, which it seizes together 370 00:23:33.119 --> 00:23:36.359 with the supporting stick, if there be one. A little 371 00:23:36.359 --> 00:23:39.720 aid is thus given in keeping the stem secure. If 372 00:23:39.720 --> 00:23:42.920 the tendril seizes nothing, it does not contract spirally, but 373 00:23:43.039 --> 00:23:46.920 soon withers away and drops off. If it seizes an object, 374 00:23:47.000 --> 00:23:51.160 all the branches contract spirally. I have stated that after 375 00:23:51.200 --> 00:23:53.680 a tendril has come into contact with a stick, it 376 00:23:53.720 --> 00:23:56.440 bends round it in about half an hour. But I 377 00:23:56.519 --> 00:23:59.680 repeatedly observed, as in the case of the speciosa and 378 00:23:59.720 --> 00:24:03.559 its allies, that it often again loosed the stick, sometimes 379 00:24:03.559 --> 00:24:06.400 seizing and losing the same stick three or four times. 380 00:24:07.200 --> 00:24:09.799 Knowing that the tendrils avoided the light, I gave them 381 00:24:09.839 --> 00:24:13.640 a glass tube blackened within and a well blackened zinc plate. 382 00:24:14.279 --> 00:24:17.680 The branches curled round the tube and abruptly bent themselves 383 00:24:17.759 --> 00:24:20.119 round the edges of the zinc plate. But they soon 384 00:24:20.200 --> 00:24:24.079 recoiled from these objects with what I can only call disgust, 385 00:24:24.480 --> 00:24:28.680 and straightened themselves. I then placed a post with extremely 386 00:24:28.759 -->

00:24:31.839 rugged bark close to a pair of tendrils. Twice they 387 00:24:31.880 --> 00:24:34.799 touched it for an hour or two, and twice they withdrew. 388 00:24:35.279 --> 00:24:38.119 At last, one of the hooked extremities curled round and 389 00:24:38.279 --> 00:24:41.680 firmly seized an excessively minute projecting point of the bark, 390 00:24:42.079 --> 00:24:45.920 and the other branches spread themselves out, following with accuracy 391 00:24:46.000 --> 00:24:49.960 every inequality of the surface. I afterwards placed near the 392 00:24:49.960 --> 00:24:53.319 plant a post without bark, but much fissured, and the 393 00:24:53.359 --> 00:24:56.240 points of the tendrils crawled into all the crevices in 394 00:24:56.279 --> 00:24:59.559 a beautiful manner. To my surprise, I observed that the 395 00:24:59.599 --> 00:25:02.680 tips of the immature tendrils, with the branches not yet 396 00:25:02.680 --> 00:25:07.640 fully separated, likewise crawled just like roots into the minutest crevices. 397 00:25:08.319 --> 00:25:10.359 In two or three days, after the tips had thus 398 00:25:10.400 --> 00:25:13.559 crawled into the crevices, or after their hooked ends had 399 00:25:13.599 --> 00:25:18.119 seized minute points, the final process now to be described commenced. 400 00:25:19.000 --> 00:25:22.279 This process I discovered by having accidentally left a piece 401 00:25:22.319 --> 00:25:25.519 of wool near a tendril, and this led me to 402 00:25:25.559 --> 00:25:30.079 bind a quantity of flax, moss and wool loosely round sticks, 403 00:25:30.240 --> 00:25:33.559 and to place them near tendrils. The wool must not 404 00:25:33.640 --> 00:25:37.519 be dyed, for these tendrils are excessively sensitive to some poisons. 405 00:25:38.000 --> 00:25:41.039 The hooked points soon caught hold of the fibers, even 406 00:25:41.119 --> 00:25:45.640 loosely floating fibers, and now there was no recoiling. On 407 00:25:45.680 --> 00:25:48.920 the contrary, the excitement caused the hooks to penetrate the 408 00:25:49.000 --> 00:25:52.440 fibrous mass and to curl inwards, so that each hook 409 00:25:52.519 --> 00:25:55.480 firmly caught one or two fibers, or a small bundle 410 00:25:55.519 --> 00:25:58.279 of them. The tips and the inner surfaces of the 411 00:25:58.279 --> 00:26:00.880 hooks now began to swell, and in two or three 412 00:26:00.920 --> 00:26:04.400 days were visibly enlarged. After a few more days, the 413 00:26:04.400 --> 00:26:08.599 hooks were converted into whitish, irregular balls rather above the 414 00:26:08.720 --> 00:26:11.880 zero point zero fifth of an inch one point two 415 00:26:12.000 --> 00:26:16.720 seven millimeters in diameter, formed of coarse cellular tissue, which 416 00:26:16.720 --> 00:26:21.720 sometimes wholly enveloped and concealed the hooks themselves. The surfaces 417 00:26:21.759 --> 00:26:25.680 of these balls secreted some vicid resinous matter to which 418 00:26:25.720 --> 00:26:29.279 the fibers of the flax et cetera adhere. When a 419 00:26:29.279 --> 00:26:33.039 fiber has become fastened to the surface, the cellular tissue 420 00:26:33.039 --> 00:26:36.079 does not grow directly beneath it, but continues to grow 421 00:26:36.160 --> 00:26:40.119 closely on each side, so that when several adjoining fibers, 422 00:26:40.200 --> 00:26:44.319 though excessively thin, were caught, so many crests of cellular matter, 423 00:26:44.720 --> 00:26:47.599 each not as thick as a human hair, grew up 424 00:26:47.640 --> 00:26:51.200 between them, and these, arching over on both sides, adhered 425 00:26:51.279 --> 00:26:54.960 firmly together. As the whole surface of the ball continues 426 00:26:55.000 --> 00:26:58.960 to grow, fresh fibers adhere and are afterwards enveloped, so 427 00:26:59.000 --> 00:27:01.720 that I have seen a little ball with between fifty 428 00:27:01.759 --> 00:27:05.559 and sixty fibers of flax crossing it at various angles, 429 00:27:05.720 --> 00:27:09.799 and all embedded more or less deeply. Every gradation in 430 00:27:09.839 --> 00:27:13.559 the process could be followed, some fibers merely sticking to 431 00:27:13.640 --> 00:27:16.599 the surface, others lying in more or less deep furrows, 432 00:27:16.680 --> 00:27:19.720 or deeply embedded, or passing through the very center of 433 00:27:19.799 --> 00:27:23.799 the circular ball. The embedded fibers are so closely clasped 434 00:27:23.799 --> 00:27:27.279 that they cannot be withdrawn. The outgrowing tissue has so 435 00:27:27.440 --> 00:27:31.000 strong a tendency to unite, that two balls produced by 436 00:27:31.039 --> 00:27:35.039 distinct tendrils sometimes unite and grow into a single one. 437 00:27:35.839 --> 00:27:38.519 On one occasion, when a tendril had curled round a 438 00:27:38.559 --> 00:27:42.119 stick half an ancient diameter, an adhesive disc was formed, 439 00:27:42.440 --> 00:27:44.720 but this does not generally occur in the case of 440 00:27:44.759 --> 00:27:48.519 smooth sticks or posts. If, however, the tip catches eate 441 00:27:48.640 --> 00:27:52.799 minute projecting point, the other branches formed discs, especially if 442 00:27:52.839 --> 00:27:56.720 they find crevices to crawl into. The tendrils failed to 443 00:27:56.759 --> 00:28:00.200 attach themselves to a brick wall. I infer from the 444 00:28:00.240 --> 00:28:02.680 adherents of the fibers to the discs or balls that 445 00:28:02.720 --> 00:28:07.039 these secrete some resinous adhesive matter, and more especially from 446 00:28:07.119 --> 00:28:11.279 such fibers becoming loose if immersed in sulfuric ether. This 447 00:28:11.440 --> 00:28:15.599 fluid likewise removes a small brown glistening points which can 448 00:28:15.839 --> 00:28:19.119 generally be seen on the surfaces of the older discs. 449 00:28:19.400 --> 00:28:23.559 If the hooked extremities of the tendrils do not touch anything, discs, 450 00:28:23.640 --> 00:28:26.079 as far as I have seen, are never formed, but 451

00:28:26.240 --> 00:28:30.559 temporary contact during a moderate time suffices to cause their development. 452 00:28:31.279 --> 00:28:34.039 I have seen eight disks formed on the same tendril. 453 00:28:34.720 --> 00:28:38.279 After their development, the tendrils contract spirally and become woody 454 00:28:38.319 --> 00:28:42.119 and very strong. A tendril in this state supported nearly 455 00:28:42.200 --> 00:28:46.519 seven ounces, and would apparently have supported a considerably greater 456 00:28:46.640 --> 00:28:49.200 weight had not the fibers of flax to which the 457 00:28:49.279 --> 00:28:53.880 discs were attached yielded. From the facts now given, we 458 00:28:54.000 --> 00:28:57.279 may infer that though the tendrils of this Bognonia can 459 00:28:57.359 --> 00:29:01.079 occasionally adhere to smooth cylindrical sticks, and often to rug 460 00:29:01.119 --> 00:29:04.920 and bark, yet they are specially adapted to climb trees 461 00:29:05.160 --> 00:29:09.200 clothed with lichens, mosses, or other such productions. And I 462 00:29:09.240 --> 00:29:14.640 hear from Professor Asa Gray that the Polypodium incannum abounds 463 00:29:14.680 --> 00:29:17.440 on the forest trees in the districts of North America 464 00:29:17.519 --> 00:29:21.599 where this species of Bignonia grows. Finally, I may remark 465 00:29:21.880 --> 00:29:24.359 how singular a fact it is that a leaf should 466 00:29:24.359 --> 00:29:28.279 be metamorphosed into a branched organ which turns from the light, 467 00:29:28.400 --> 00:29:31.400 and which can, by its extremities, either crawl like roots 468 00:29:31.440 --> 00:29:35.559 into crevices or seize hold of minute projecting points. These 469 00:29:35.599 --> 00:29:40.880 extremities afterwards forming cellular outgrowths, which crete an adhesive cement, 470 00:29:41.240 --> 00:29:45.200 and then envelop by their continued growth. The finest fibers 471 00:29:46.799 --> 00:29:52.559 A Cremocarpus scaber. Big Nonacia plants, though growing pretty well 472 00:29:52.640 --> 00:29:56.039 in my greenhouse, showed no spontaneous movement in their shoots 473 00:29:56.079 --> 00:29:59.240 or tendrils, but when removed to the hot house, the 474 00:29:59.359 --> 00:30:02.759 young intern revolved at rates varying from three hours fifteen 475 00:30:02.839 --> 00:30:06.480 minutes to one hour thirteen minutes. One large circle was 476 00:30:06.519 --> 00:30:10.240 swept at this latter unusually thick rate, but generally the 477 00:30:10.279 --> 00:30:13.880 circles or ellipses were small, and sometimes the course pursued 478 00:30:13.960 --> 00:30:18.640 was quite irregular. An internode, after making several revolutions, sometimes 479 00:30:18.680 --> 00:30:22.160 stood still for twelve hours or eighteen hours, and then 480 00:30:22.279 --> 00:30:26.759 recommenced revolving. Such strongly marked interruption in the movements of 481 00:30:26.799 --> 00:30:29.880 the internodes I have observed in hardly any other plant. 482

00:30:30.359 --> 00:30:35.480 The leaves bear four leaflets, themselves subdivided and terminate in 483 00:30:35.680 --> 00:30:39.640 much branched tandrils. The main petule of the leaf, whilst young, 484 00:30:39.880 --> 00:30:44.240 moves spontaneously and follows nearly the same irregular course and 485 00:30:44.599 --> 00:30:48.279 at above the same rate as the internodes. The movement 486 00:30:48.440 --> 00:30:51.319 to and from the stem is the most conspicuous, and 487 00:30:51.400 --> 00:30:53.640 I have seen the cord of a curved petule which 488 00:30:53.720 --> 00:30:56.000 formed at an angle of fifty nine degrees, with the 489 00:30:56.039 --> 00:30:58.839 stem in an hour afterwards make an angle of one 490 00:30:58.920 --> 00:31:02.519 hundred and six degrees. The two opposite pedules do not 491 00:31:02.599 --> 00:31:05.319 move together, and one is sometimes so much raised as 492 00:31:05.359 --> 00:31:08.079 to stand close to the stem, whilst the other is 493 00:31:08.160 --> 00:31:11.680 not far from horizontal. The basal part of the petule 494 00:31:11.799 --> 00:31:15.279 moves less than the distal part. The tendrils, besides being 495 00:31:15.359 --> 00:31:20.039 carried by the moving petioles and internodes them spelves move spontaneously, 496 00:31:20.359 --> 00:31:24.200 and the opposite tendrils occasionally move in opposite directions. By 497 00:31:24.279 --> 00:31:27.920 these combined movements of the young internodes, petioles, and tendrils, 498 00:31:27.960 --> 00:31:30.720 a considerable space is swept in search of a support. 499 00:31:31.920 --> 00:31:34.960 In young plants, the tendrils are about three inches in length. 500 00:31:35.359 --> 00:31:38.319 They bear two lateral and two terminal branches, and each 501 00:31:38.400 --> 00:31:42.559 branch bifurcates twice, with the tips terminating in blunt double hooks, 502 00:31:42.599 --> 00:31:46.079 having both points directed to the same side. All the 503 00:31:46.119 --> 00:31:49.519 branches are sensitive on all sides, and after being lightly 504 00:31:49.599 --> 00:31:52.599 rubbed or after coming into contact with a stick, bend 505 00:31:52.680 --> 00:31:55.680 in about ten minutes. One which had become curved in 506 00:31:55.720 --> 00:31:58.839 ten minutes after a light rub, continued bending for between 507 00:31:58.880 --> 00:32:01.799 three hours and four hour, and became straight again in 508 00:32:01.920 --> 00:32:05.279 eight hours or nine hours. Tendrils which have caught nothing 509 00:32:05.359 --> 00:32:09.119 ultimately contract into an irregular spire, as they likewise do, 510 00:32:09.240 --> 00:32:13.440 only much more quickly after clasping a support. In both cases, 511 00:32:13.480 --> 00:32:16.480 the main petule bearing be leafless, which is at first 512 00:32:16.519 --> 00:32:19.920 strate and inclined a little upwards, moves downwards, with the 513 00:32:19.920 --> 00:32:23.240 middle part bent abruptly into a right angle. But this 514 00:32:23.440 --> 00:32:27.920 is seen in Emnitis more plainly than in e. Scabber. 515 00:32:28.839 --> 00:32:31.680 The tendrils in this genus act in some respects like 516 00:32:31.720 --> 00:32:35.240 those of Ignonia capriolata, but the whole does not move 517 00:32:35.240 --> 00:32:38.319 from the light, nor do the hooked tips become enlarged 518 00:32:38.359 --> 00:32:42.319 into circular discs. After the tendrils have come into contact 519 00:32:42.359 --> 00:32:45.319 with a moderately thick cylindrical stick or with rugged bark, 520 00:32:45.680 --> 00:32:48.960 the several branches may be seen slowly to lift themselves up, 521 00:32:49.279 --> 00:32:52.160 changing their positions, and again come into contact with the 522 00:32:52.200 --> 00:32:56.240 supporting surface. The object of these movements is to bring 523 00:32:56.240 --> 00:32:58.599 the double hooks at the extremity of the branches, which 524 00:32:58.680 --> 00:33:02.119 naturally face in all directions, into contact with the wood. 525 00:33:02.880 --> 00:33:05.279 I have watched the tendril half of which had bent 526 00:33:05.400 --> 00:33:08.440 itself at right angles round the sharp corner of a 527 00:33:08.480 --> 00:33:12.480 square post, neatly bring every single hook into contact with 528 00:33:12.599 --> 00:33:17.319 both rectangular surfaces. The appearance suggested the belief that though 529 00:33:17.359 --> 00:33:20.359 the whole tendril is not sensitive to light, yet that 530 00:33:20.440 --> 00:33:23.119 the tips are so, and that they turn and twist 531 00:33:23.160 --> 00:33:27.920 themselves towards any dark surface. Ultimately, the branches arrange themselves 532 00:33:28.039 --> 00:33:31.200 very neatly into all the irregularities of the most rugged bark, 533 00:33:31.440 --> 00:33:34.039 so that they resemble in their irregular course a river 534 00:33:34.119 --> 00:33:37.400 with its branches as engraved on a map. But when 535 00:33:37.400 --> 00:33:41.559 its tendril has wound round a rather thick stick, the 536 00:33:41.599 --> 00:33:45.880 subsequent spiral contraction generally draws it away and spoils the 537 00:33:45.960 --> 00:33:49.680 neat arrangement. So it is, but not in quite so 538 00:33:49.920 --> 00:33:52.920 marked a manner. When a tendril has spread itself over 539 00:33:52.960 --> 00:33:56.599 a large, nearly flat surface of rugged bark, we may 540 00:33:56.640 --> 00:34:00.000 therefore conclude that these tendrils are not perfectly adapted to 541 00:34:00.160 --> 00:34:04.160 seize moderately thick sticks or rugged barb. If a thin 542 00:34:04.279 --> 00:34:07.400 stick or twig is placed near a tendril, the terminal 543 00:34:07.440 --> 00:34:10.920 branches wind quite round it and then sees their own 544 00:34:10.960 --> 00:34:14.039 lower branches or the main stand. The stick is thus 545 00:34:14.079 --> 00:34:17.800 firmly but not neatly grasped. What the tendrils are really 546 00:34:17.840 --> 00:34:20.599 adapted for appears to

be such objects as the thin 547 00:34:20.760 --> 00:34:24.119 culumns of certain grasses, or the long, flexible bristles of 548 00:34:24.119 --> 00:34:26.800 a brush, or thin, rigid leaves such as those of 549 00:34:26.800 --> 00:34:30.559 the asparagus, all of which they sees in an admirable manner. 550 00:34:31.360 --> 00:34:33.920 This is due to the extremities of the branches close 551 00:34:33.960 --> 00:34:36.840 to the little hooks being extremely sensitive to a touch 552 00:34:36.880 --> 00:34:41.079 from the thinnest object, which they consequently curl round and clasp. 553 00:34:41.800 --> 00:34:44.960 When a small brush, for instance, was placed near a tendril, 554 00:34:45.000 --> 00:34:48.199 the tips of each sub branch seized one, two or 555 00:34:48.239 --> 00:34:51.519 three of the bristles, and then the spiral contraction of 556 00:34:51.559 --> 00:34:54.920 the several branches brought all these little parcels close together, 557 00:34:55.320 --> 00:34:58.159 so that thirty or forty bristles were drawn into a 558 00:34:58.159 --> 00:35:05.760 single bundle, which afforded an excellent support. Pulmonacea corborascandons this 559 00:35:05.920 --> 00:35:09.679 is an excellently constructed climber. The tendrils on a fine 560 00:35:09.719 --> 00:35:12.599 plant were eleven inches long, with a petial bearing two 561 00:35:12.599 --> 00:35:15.679 pairs of leaflets only two and a half inches in length. 562 00:35:16.199 --> 00:35:19.000 They revolve more rapidly and more vigorously than those of 563 00:35:19.039 --> 00:35:22.079 any other tendril bearer observed by me, With the exception 564 00:35:22.159 --> 00:35:26.679 of one kind of passiflora, three large nearly circular sweeps 565 00:35:26.719 --> 00:35:29.679 directed against the sun were completed each in one hour 566 00:35:29.760 --> 00:35:33.199 fifteen minutes, and to other circles in one hour twenty 567 00:35:33.239 --> 00:35:37.159 minutes and one hour twenty three minutes. Sometimes a tendril 568 00:35:37.199 --> 00:35:40.519 travels in a much inclined position, and sometimes nearly upright. 569 00:35:41.119 --> 00:35:43.760 The lower part moves but little, and the petule not 570 00:35:43.880 --> 00:35:46.840 at all, Nor do the internodes revolve, so that here 571 00:35:46.920 --> 00:35:50.800 we have the tendril alone moving. On the other hand, 572 00:35:50.920 --> 00:35:55.920 with most of the species of Bignonia and Ecromocarpus, the internodes, tendrils, 573 00:35:55.920 --> 00:36:00.360 and petioles all revolved. The long, straight, tapering mains stem 574 00:36:00.400 --> 00:36:04.000 of the tendril of the Koboi bears alternate branches, and 575 00:36:04.119 --> 00:36:07.760 each branch is several times divided, with the finer branches 576 00:36:07.800 --> 00:36:11.719 as thin as very thin bristles and extremely flexible, so 577 00:36:11.760 --> 00:36:14.000 that they are blown about by a breath of air. 578 00:36:14.599 --> 00:36:18.000 Yet they are strong and highly

elastic. The extremity of 579 00:36:18.039 --> 00:36:20.719 each branch is a little flattened and terminates in a 580 00:36:20.760 --> 00:36:24.519 minute double though sometimes single hook formed of a hard 581 00:36:24.559 --> 00:36:28.480 translucent woody substance, and as sharp as the finest needle 582 00:36:29.159 --> 00:36:32.079 on a tendril which was eleven inches long. I counted 583 00:36:32.199 --> 00:36:36.320 ninety four of these beautifully constructed little hooks. They readily 584 00:36:36.400 --> 00:36:38.880 catch soft wood or gloves, or the skin of the 585 00:36:39.000 --> 00:36:42.480 naked hand. With the exception of these hardened hooks and 586 00:36:42.599 --> 00:36:45.400 of the basal part of the central stem, every part 587 00:36:45.480 --> 00:36:48.599 of each branchlet is highly sensitive on all sides to 588 00:36:48.679 --> 00:36:51.760 a slight touch, and bends in a few minutes towards 589 00:36:51.760 --> 00:36:55.639 the touch side by lightly rubbing several sub branches on 590 00:36:55.679 --> 00:37:00.840 opposite sides. The whole tendril rapidly assumed an extraordinarily shape. 591 00:37:01.039 --> 00:37:04.480 These movements from contact do not interfere with the ordinary 592 00:37:04.519 --> 00:37:08.960 revolving movement. The branches, after becoming greatly curved from being touched, 593 00:37:09.199 --> 00:37:12.519 straighten themselves at a quicker rate than in almost any 594 00:37:12.559 --> 00:37:15.719 other tendril seen by me, namely in about half an 595 00:37:15.760 --> 00:37:19.920 hour and an hour after the tendril has caught any object. 596 00:37:20.000 --> 00:37:24.400 Spiral contraction likewise begins after an unusually short period of time, 597 00:37:24.800 --> 00:37:28.719 namely in about twelve hours before the tendril is mature, 598 00:37:29.000 --> 00:37:33.320 the terminal branchlets cohere and the hooks are curled closely inwards. 599 00:37:33.719 --> 00:37:36.360 At this point no part is sensitive to a touch, 600 00:37:36.599 --> 00:37:39.079 but as soon as the branches diverge and the hooks 601 00:37:39.079 --> 00:37:43.360 stand out, full sensitiveness is acquired. It is a singular 602 00:37:43.400 --> 00:37:47.719 circumstance that immature tendrils revolve at their full velocity before 603 00:37:47.719 --> 00:37:51.559 they become sensitive, but in a useless manner, as in 604 00:37:51.599 --> 00:37:56.079 this state they can catch nothing. This want of perfect coadaptation, 605 00:37:56.559 --> 00:37:59.159 though only for a short time between the structure and 606 00:37:59.199 --> 00:38:01.599 the function of a climbing plant, is a rare event. 607 00:38:02.679 --> 00:38:05.000 A tendril, as soon as it is ready to act, 608 00:38:05.079 --> 00:38:09.760 stands together with the supporting petiole, vertically upwards. The leaflets 609 00:38:09.800 --> 00:38:12.639 borne by the petiole are at this time quite small, 610 00:38:12.880 --> 00:38:15.079 and the extremity of the growing stem is bent to 611 00:38:15.199 --> 00:38:17.239 one side so as to be out of the way 612 00:38:17.360 --> 00:38:21.320 of the revolving tendril, which sweeps large circles directly overhead. 613 00:38:21.920 --> 00:38:24.960 The tendrils thus revolve in a position well adapted for 614 00:38:25.000 --> 00:38:28.239 the catching of objects standing above, and by this means 615 00:38:28.280 --> 00:38:31.760 the ascent of the plant is favored. If no object 616 00:38:31.800 --> 00:38:34.599 is caught, the leaf with its tendril bends downward and 617 00:38:34.760 --> 00:38:39.079 ultimately assumes a horizontal position. An open space is thus 618 00:38:39.320 --> 00:38:42.760 left for the next succeeding and younger tendril to stand 619 00:38:42.920 --> 00:38:46.519 vertically upwards and to revolve freely. As soon as an 620 00:38:46.559 --> 00:38:50.239 old tendril bends downward, it loses all power of movement 621 00:38:50.559 --> 00:38:54.880 and contracts spirally into an entangled mass. Although the tendrils 622 00:38:54.920 --> 00:38:58.480 revolve with unusual rapidity, the movement lasts for only a 623 00:38:58.519 --> 00:39:01.760 short time. In a plant placed in the hothouse and 624 00:39:01.800 --> 00:39:05.840 growing vigorously, a tendril revolve for not longer than thirty 625 00:39:05.880 --> 00:39:09.519 six hours, counting from the period when it first became sensitive, 626 00:39:10.079 --> 00:39:13.199 But during this period it probably made at least twenty 627 00:39:13.239 --> 00:39:17.840 seven revolutions. When a revolving tendril strikes against a stick, 628 00:39:17.920 --> 00:39:21.159 the branches quickly bend round and clasp it. The little 629 00:39:21.199 --> 00:39:24.280 hooks here play an important part, as they prevent the 630 00:39:24.280 --> 00:39:27.519 branches from being dragged away by the rapid revolving movement 631 00:39:27.800 --> 00:39:31.039 before they have had time to clasp the sticks curely. 632 00:39:31.760 --> 00:39:34.480 This is especially the case when only the extremity of 633 00:39:34.519 --> 00:39:37.400 a branch has caught hold of a support. As soon 634 00:39:37.440 --> 00:39:40.639 as a tendril has bend a smooth stick or a 635 00:39:40.719 --> 00:39:45.119 thick rugged post or has come into contact with planed wood, 636 00:39:45.400 --> 00:39:48.360 for it can adhere temporarily, even to so smooth a 637 00:39:48.440 --> 00:39:52.480 surface as this. The same peculiar movements may be observed 638 00:39:52.519 --> 00:39:57.840 as those described under Bignonia capriolata and a creamocarpas the 639 00:39:57.880 --> 00:40:01.920 branches repeatedly lift themselves up and down, those which have 640 00:40:02.440 --> 00:40:06.360 their hooks already directed downwards, remaining in this position and 641 00:40:06.440 --> 00:40:09.880 securing the tendril, whilst the others twist about until they 642 00:40:09.920 --> 00:40:14.039 succeed in arranging themselves in conformity with every irregularity of 643

00:40:14.079 --> 00:40:17.360 the surface, and in bringing their hooks into contact with 644 00:40:17.400 --> 00:40:20.320 the wood. The use of the hooks was well shown 645 00:40:20.440 --> 00:40:23.719 by giving the tendrils tubes and slips of glass to catch, 646 00:40:24.159 --> 00:40:28.239 for these, though temporarily seased, were invariably lost, either during 647 00:40:28.239 --> 00:40:32.280 the rearrangement of the branches or ultimately when spiral contraction ensued. 648 00:40:33.400 --> 00:40:36.679 The perfect manner in which the branches arrange themselves, creeping 649 00:40:36.760 --> 00:40:39.840 like rootlets over every inequality of the surface and into 650 00:40:39.960 --> 00:40:43.199 any deep crevice, is a pretty sight, for it is 651 00:40:43.280 --> 00:40:47.400 perhaps more effectively performed by this than by any other species. 652 00:40:48.000 --> 00:40:51.519 The action is certainly more conspicuous, as the upper surfaces 653 00:40:51.559 --> 00:40:54.239 of the main stem, as well as of every branch 654 00:40:54.320 --> 00:40:57.880 to the extreme hooks, are angular and green, whilst the 655 00:40:57.920 --> 00:41:01.800 lower surfaces are rounded and purple. I was led to infer, 656 00:41:01.920 --> 00:41:05.199 as in former cases, that a less amount of light 657 00:41:05.280 --> 00:41:08.400 guided these movements of the branches of the tendrils. I 658 00:41:08.480 --> 00:41:11.599 made many trials with black and white cards and glass 659 00:41:11.639 --> 00:41:15.119 tubes to prove it, but failed from various causes. Yet 660 00:41:15.159 --> 00:41:19.400 these trials countenanced the belief. As a tendril consists of 661 00:41:19.440 --> 00:41:22.679 the leafs split into numerous segments, there is nothing surprising 662 00:41:22.800 --> 00:41:26.559 in all that the segments turning their proper surfaces towards 663 00:41:26.559 --> 00:41:28.639 the light as soon as the tendril is caught and 664 00:41:28.679 --> 00:41:32.400 the revolving movement is arrested. But this will not account 665 00:41:32.440 --> 00:41:35.519 for the whole movement, for the segments actually bend or 666 00:41:35.599 --> 00:41:38.559 curve to the dark side, besides turning round on their 667 00:41:38.599 --> 00:41:41.599 axis so that their upper surfaces may face the light. 668 00:41:42.480 --> 00:41:46.119 When koboe grows in the open air, the wind must 669 00:41:46.159 --> 00:41:49.920 aid the extremely flexible tendrils. In seizing a support for 670 00:41:50.039 --> 00:41:53.159 I found that a mere breath sufficed to cause the 671 00:41:53.199 --> 00:41:56.480 extreme branches to catch hold by their hooks of twigs 672 00:41:56.760 --> 00:41:59.480 which they could not have reached by the revolving movement. 673 00:42:00.440 --> 00:42:03.039 It might have been taught that a tendril thus hooked 674 00:42:03.039 --> 00:42:05.639 by the extremity of a single branch could not have 675 00:42:05.760 --> 00:42:09.679 fairly grasped its support. But several times I watched cases 676 00:42:09.760 --> 00:42:13.320 like the following tendril caught a thin stick by the 677 00:42:13.360 --> 00:42:17.360 hooks of one of its two extreme branches. Though thus 678 00:42:17.400 --> 00:42:20.840 held by the tip, it still tried to revolve, bowing 679 00:42:20.920 --> 00:42:23.960 itself to all sides, and by this movement to the 680 00:42:24.000 --> 00:42:28.159 other extreme branch soon caught the stick. The first branch 681 00:42:28.199 --> 00:42:31.880 then loosed itself and arranging its hook again, caught hold. 682 00:42:32.599 --> 00:42:35.280 After a time, from the continued movement of the tendril, 683 00:42:35.519 --> 00:42:38.599 the hooks of a third branch caught hold. No other 684 00:42:38.639 --> 00:42:41.920 branches as the tendril then stood, could possibly have touched 685 00:42:41.920 --> 00:42:44.840 the stick. But before long the upper part of the 686 00:42:44.840 --> 00:42:48.679 main stem began to contract into an open spire. It 687 00:42:48.760 --> 00:42:52.039 thus dragged the chute which bore the tendril, towards the stick, 688 00:42:52.360 --> 00:42:56.119 and as the tendril continually tried to revolve, a fourth 689 00:42:56.119 --> 00:43:01.440 branch was brought into contact, and lastly from the spiral contraction, 690 00:43:01.639 --> 00:43:04.639 traveling down both of the main stem and the branches. 691 00:43:05.079 --> 00:43:08.480 All of them, one after another, were ultimately brought into 692 00:43:08.559 --> 00:43:12.199 contact with the stick. They then wound themselves round it 693 00:43:12.320 --> 00:43:16.480 and round one another, until the whole tendril was tied 694 00:43:16.599 --> 00:43:22.119 together in inextricable knot. The tendrils, though at first quite flexible, 695 00:43:22.599 --> 00:43:25.440 after having clasped a support for a time, become more 696 00:43:25.519 --> 00:43:28.719 rigid and stronger than they were at first. Thus the 697 00:43:28.760 --> 00:43:31.800 plant is secured to its support in a perfect manner. 698 00:43:33.440 --> 00:43:38.599 Leguminosae pisum setabum, the common p was the subject of 699 00:43:38.719 --> 00:43:42.559 a valuable memoir by Dutrecia, who discovered that the internodes 700 00:43:42.559 --> 00:43:46.719 and tendrils revolve in ellipses. The ellipses are generally very narrow, 701 00:43:46.760 --> 00:43:50.960 but sometimes approached to circles. I several times observed that 702 00:43:51.039 --> 00:43:54.880 the longer axis slowly changed its direction, which is of importance, 703 00:43:54.960 --> 00:43:58.639 as the tendril thus sweeps a wider space. Owing to 704 00:43:58.679 --> 00:44:01.519 this change of direction, and likewise to the movement of 705 00:44:01.519 --> 00:44:05.400 the stem towards the light, the successive irregular ellipses generally 706 00:44:05.440 --> 00:44:09.000 form an irregular spire. I have thought it worthwhile to 707 00:44:09.000 --> 00:44:12.400 annex a tracing of the course

pursued by the upper internode, 708 00:44:12.559 --> 00:44:15.960 the movement of the tendril being neglected of a small plant. 709 00:44:16.079 --> 00:44:21.000 From eight forty am to nine fifteen pm. The course 710 00:44:21.119 --> 00:44:24.159 was traced on a hemispherical glass placed over the plant, 711 00:44:24.239 --> 00:44:27.800 and the dots with figures give the hours of the observation, 712 00:44:28.320 --> 00:44:32.000 each dot being joined by a straight line. No doubt, 713 00:44:32.119 --> 00:44:35.079 all the lines would have been curvelinear if the course 714 00:44:35.119 --> 00:44:39.239 had been observed at much shorter intervals. The extremity of 715 00:44:39.239 --> 00:44:42.639 the petiole from which the young tendril arose was two 716 00:44:42.639 --> 00:44:45.039 inches from the glass, so that if a pencil two 717 00:44:45.079 --> 00:44:47.360 inches in length could have been affixed to the petiole, 718 00:44:47.679 --> 00:44:50.400 it would have traced the annexed figure on the underside 719 00:44:50.400 --> 00:44:52.679 of the glass. But it must be remembered that the 720 00:44:52.679 --> 00:44:56.480 figure is reduced by one half neglecting the first great 721 00:44:56.519 --> 00:44:59.760 sweep towards the light from the figure one to two. 722 00:45:00.239 --> 00:45:03.079 The end of the petule swept a graceful four inches 723 00:45:03.079 --> 00:45:06.599 across in one direction and three inches in another. As 724 00:45:06.639 --> 00:45:09.920 a full grown tendril is considerably above two inches in length, 725 00:45:09.960 --> 00:45:13.039 and as the tendril itself bends and revolves in harmony 726 00:45:13.360 --> 00:45:16.559 with the internode, a considerably wider space is swept than 727 00:45:16.639 --> 00:45:21.159 is here represented on a reduced scale. Detrocie observed the 728 00:45:21.280 --> 00:45:24.360 completion of an ellipse in one hour twenty minutes. I 729 00:45:24.440 --> 00:45:27.599 saw one completed in one hour thirty minutes. The direction 730 00:45:27.760 --> 00:45:31.199 followed is variable either with or against the sun. D 731 00:45:31.360 --> 00:45:35.000 Trocie asserts that the petioles of the leafs spontaneously revolve, 732 00:45:35.079 --> 00:45:38.039 as well as the young internodes and tendrils, but he 733 00:45:38.119 --> 00:45:41.119 does not say that he secured the internodes, which when 734 00:45:41.159 --> 00:45:43.960 this was done, I could never detect any movement in 735 00:45:43.960 --> 00:45:48.039 the petiole except to and from the light. The tendrils, 736 00:45:48.159 --> 00:45:51.199 on the other hand, when the internodes and petioles are secured, 737 00:45:51.440 --> 00:45:55.639 describe irregular spires or regular ellipses exactly like those made 738 00:45:55.679 --> 00:45:59.039 by the internodes. A young tendril only one one eighth 739 00:45:59.119 --> 00:46:02.559 of an inch in length revolved. Dutrochet has shown that 740 00:46:02.599 --> 00:46:04.480 when a plant is

placed in a room so that 741 00:46:04.559 --> 00:46:08.000 the light enters laterally, the internodes travel much quicker to 742 00:46:08.000 --> 00:46:10.719 the light than from it. On the other hand, he 743 00:46:10.760 --> 00:46:13.920 asserts that the tendril itself moves from the lights towards 744 00:46:13.960 --> 00:46:16.800 the dark side of the room. With due deference to 745 00:46:16.840 --> 00:46:19.920 this great observer. I think he was mistaken owing to 746 00:46:19.960 --> 00:46:23.280 his not having secured the internodes. I took a young 747 00:46:23.360 --> 00:46:26.679 plant with highly sensitive tendrils and tied the petiole so 748 00:46:26.719 --> 00:46:29.679 that the tendril alone could move. It completed a perfect 749 00:46:29.719 --> 00:46:32.519 ellipse in one hour thirty minutes. I then turned the 750 00:46:32.559 --> 00:46:35.519 plant partly round, but this made no change in the 751 00:46:35.519 --> 00:46:39.039 direction of the succeeding ellipse. The next day I walked 752 00:46:39.079 --> 00:46:42.920 a plant similarly secured until the tendril, which was highly sensitive, 753 00:46:43.000 --> 00:46:45.440 making the lips in a line exactly to and from 754 00:46:45.480 --> 00:46:48.440 the light. The movement was so great that the tendril 755 00:46:48.480 --> 00:46:51.519 at the two ends of its elliptrical course bent itself 756 00:46:51.559 --> 00:46:55.199 a little beneath the horizon, thus traveling more than one 757 00:46:55.239 --> 00:46:59.320 hundred eighty degrees. But the curvature was fully as great 758 00:46:59.400 --> 00:47:01.719 towards the life light as towards the dark side of 759 00:47:01.760 --> 00:47:05.960 the rope. I believe Deutroche was misled by not having 760 00:47:05.960 --> 00:47:09.159 secured the internodes, and by having observed the plant of 761 00:47:09.199 --> 00:47:12.679 which the internodes and tendrils no longer curved in harmony 762 00:47:12.679 --> 00:47:17.960 together owing to inequality of age. Ditoche made no observation 763 00:47:18.239 --> 00:47:21.719 on the sensitiveness of the tendrils. These, whilst young and 764 00:47:21.760 --> 00:47:24.239 about an ancient length with the leaflets on the petio 765 00:47:24.360 --> 00:47:28.639 only partially expanded, are highly sensitive. A single light touch 766 00:47:28.679 --> 00:47:31.440 with a twig on the inferior or concave surface near 767 00:47:31.480 --> 00:47:34.920 the tip caused them to bend quickly, as did occasionally 768 00:47:34.960 --> 00:47:37.760 a loop of thread weighing one seventh of a grain 769 00:47:38.159 --> 00:47:42.199 nine point twenty five milligrams. The upper convex surface is 770 00:47:42.199 --> 00:47:46.199 barely or not at all sensitive. Tendrils, after bending from 771 00:47:46.199 --> 00:47:49.239 a touch, straightened themselves in about two hours and are 772 00:47:49.280 --> 00:47:52.480 then ready to act again. As soon as they began 773 00:47:52.559 --> 00:47:55.079 to grow old. The extremities of their two or three 774 00:47:55.119 --> 00:47:58.119 pairs of branches become hooked, and they then appear to 775 00:47:58.119 --> 00:48:01.679 form an excellent grappling instrument. But this is not the case, 776 00:48:02.159 --> 00:48:05.960 for at this period they have generally quite lost their sensitiveness, 777 00:48:06.199 --> 00:48:09.360 and when hooked onto twigs, some were not at all affected, 778 00:48:09.639 --> 00:48:12.760 and others required from eighteen hours to twenty four hours 779 00:48:12.880 --> 00:48:17.360 before clasping such twigs. Nevertheless, they were unable to utilize 780 00:48:17.480 --> 00:48:23.320 this last vestige of irritability owing to their extremities being hooked. Ultimately, 781 00:48:23.400 --> 00:48:27.000 their lateral branches contract spirally, but not the middle or 782 00:48:27.039 --> 00:48:33.599 main stem. Athirus afhaca. This plant is destitute of leaves 783 00:48:33.639 --> 00:48:37.920 except during a very early age, these being replaced by tendrils, 784 00:48:38.000 --> 00:48:42.079 and the leaves themselves by large stipules. It might therefore 785 00:48:42.079 --> 00:48:45.679 have been expected that the tendrils would have been highly organized, 786 00:48:45.880 --> 00:48:49.039 but this is not so. They are moderately long, thin, 787 00:48:49.199 --> 00:48:53.039 and unbranched, with their tips slightly curved. Whilst young, they 788 00:48:53.079 --> 00:48:56.199 are sensitive on all sides, but chiefly on the concave 789 00:48:56.320 --> 00:49:00.639 side of the extremity. They have no spontaneous revolving, but 790 00:49:00.840 --> 00:49:03.599 are at first inclined upwards at an angle of about 791 00:49:03.639 --> 00:49:07.599 forty five degrees, then move into a horizontal position and 792 00:49:07.719 --> 00:49:11.760 ultimately bend downwards. The young internodes, on the other hand, 793 00:49:11.880 --> 00:49:15.639 revolve in ellipses and carry with them the tendrils. Two 794 00:49:15.719 --> 00:49:19.639 ellipses were completed each and nearly five hours. Their longer 795 00:49:19.679 --> 00:49:22.880 axes were directed at about an angle of forty five 796 00:49:22.960 --> 00:49:28.599 degrees to the axis of the previously made ellipse. Latharus grendiflorus. 797 00:49:29.199 --> 00:49:33.239 The plants observed were young and not growing vigorously yet sufficiently, 798 00:49:33.320 --> 00:49:36.840 so I think for my observations to be trusted. If so, 799 00:49:37.000 --> 00:49:40.480 we have the rare case of neither internodes nor tendrils revolving. 800 00:49:41.119 --> 00:49:43.880 The tendrils of vigorous plants are above four inches in 801 00:49:43.960 --> 00:49:47.519 length and are often twice divided into three branches. The 802 00:49:47.559 --> 00:49:50.679 tips are curved and are sensitive on their concave sides. 803 00:49:51.039 --> 00:49:53.719 The lower part of the central stem is hardly sensitive 804 00:49:53.760 --> 00:49:56.800 at all. Hence, these

plants appear to climb simply by 805 00:49:56.800 --> 00:49:59.199 its tendrils being brought through the growth of the stem, 806 00:49:59.519 --> 00:50:03.000 or more f by the wind into contact with surrounding objects, 807 00:50:03.239 --> 00:50:06.480 which they then clasp. I may add that the tendrils 808 00:50:06.559 --> 00:50:11.920 or the internodes, or both of Visia satvia revolve Compostia 809 00:50:12.159 --> 00:50:17.920 Mutisia calmatis. The immense family of the Compositae, is well 810 00:50:18.039 --> 00:50:21.480 known to include very few climbing plants. We have seen 811 00:50:21.559 --> 00:50:24.679 in the table in the first chapter that Meccania scandons 812 00:50:24.800 --> 00:50:27.679 is a regular twiner, and F. Muller informs me that 813 00:50:27.840 --> 00:50:30.920 in South Brazil there is another species which is a 814 00:50:31.000 --> 00:50:34.400 leaf climber. Mutisia is the only genus in the family 815 00:50:34.519 --> 00:50:37.320 as far as I can learn, which bears tendrils. It 816 00:50:37.440 --> 00:50:40.800 is therefore interesting to find that these, though rather less 817 00:50:40.880 --> 00:50:45.960 metamorphosed from their primordial folier condition than are most other tendrils, 818 00:50:46.400 --> 00:50:50.639 yet display all the ordinary characteristic movements, both those that 819 00:50:50.719 --> 00:50:54.760 are spontaneous and those which are excited by contact. The 820 00:50:54.880 --> 00:50:58.480 long leaf bears seven or eight alternate leaflets and terminates 821 00:50:58.559 --> 00:51:01.280 in a tendril, which, in a place of considerable size 822 00:51:01.440 --> 00:51:05.719 was five inches in length. It consists generally of three branches, 823 00:51:06.119 --> 00:51:10.800 and these, although much elongated, evidently represent the petioles and 824 00:51:10.920 --> 00:51:14.559 midribs of three leaflets, for they closely resemble the same 825 00:51:14.679 --> 00:51:17.760 parts in an ordinary leaf, in being rectangular on the 826 00:51:17.880 --> 00:51:22.800 upper surface, furrowed and edged with green. Moreover, the green 827 00:51:22.960 --> 00:51:26.159 edging of the tendrils of young plants sometimes expands into 828 00:51:26.199 --> 00:51:29.599 a narrow lamina or blade. Each branch is curved a 829 00:51:29.639 --> 00:51:33.320 little downwards and is slightly hooked at the extremity. A 830 00:51:33.440 --> 00:51:37.440 young upper internode revolved, judging from three revolutions at an 831 00:51:37.480 --> 00:51:40.559 average rate of one hour thirty eight minutes. Its swept 832 00:51:40.599 --> 00:51:43.840 ellipses with the longer axi is directed at right angles 833 00:51:43.880 --> 00:51:47.800 to one another, but the plant apparently cannot twine. The 834 00:51:47.920 --> 00:51:51.239 petioles and the tendrils are both in constant movement, but 835 00:51:51.360 --> 00:51:54.920 their movement is slower and much less regularly elliptical than 836 00:51:55.000 --> 00:51:58.320 that

of the internodes. They appear to be much affected 837 00:51:58.360 --> 00:52:00.960 by the light, for the whole leaf usually sinks down 838 00:52:01.079 --> 00:52:04.199 during the night and rises during the day, moving also 839 00:52:04.400 --> 00:52:06.679 during the day in a crooked course to the west. 840 00:52:07.400 --> 00:52:09.599 The tip of the tendril is highly sensitive on the 841 00:52:09.679 --> 00:52:12.360 lower surface, and one which was just touched with a 842 00:52:12.400 --> 00:52:15.719 twig became perceptibly curved in three minutes and another in 843 00:52:15.840 --> 00:52:19.639 five minutes. The upper surface is not at all sensitive. 844 00:52:20.119 --> 00:52:23.320 The sides are moderately sensitive, so that the two branches 845 00:52:23.440 --> 00:52:26.519 which were rubbed on their inner sides converged and crossed 846 00:52:26.559 --> 00:52:29.800 each other. The petrole of the leaf, and the lower 847 00:52:29.880 --> 00:52:33.079 parts of the tendril halfway between the upper leaflet and 848 00:52:33.159 --> 00:52:37.159 the lowest branch are not sensitive. A tendril, after curling 849 00:52:37.199 --> 00:52:39.920 from a touch became straight again in about six hours 850 00:52:40.000 --> 00:52:43.039 and was ready to react, but one that had been 851 00:52:43.239 --> 00:52:45.960 so roughly rubbed as to have coiled into a helix 852 00:52:46.360 --> 00:52:50.320 did not become perfectly straight until after thirteen hours. The 853 00:52:50.440 --> 00:52:54.599 tendrils retained their sensibility to an unusually bit age. For 854 00:52:54.760 --> 00:52:57.199 one born by a leaf with five or six fully 855 00:52:57.280 --> 00:53:01.599 developed leafs above was still active. If a tendril catches 856 00:53:01.679 --> 00:53:04.960 nothing After considerable interval of time. The tips of the 857 00:53:05.000 --> 00:53:08.840 branches curl a little inwards, but if it clasps some object, 858 00:53:08.960 --> 00:53:16.880 the whole contracts spirally. Simulaceae similax aspera variation Maculata august 859 00:53:17.199 --> 00:53:21.599 Saint Hilaire considers the tendrils which rise in pairs from 860 00:53:21.639 --> 00:53:26.239 the petiole are modified lateral leaflets, but mole page forty 861 00:53:26.280 --> 00:53:30.679 one ranks them as modified stipules. These tendrils are from 862 00:53:30.719 --> 00:53:32.719 one and a half to one of three fourths inches 863 00:53:32.760 --> 00:53:36.079 in length, are thin, and have slightly curved, pointed extremities. 864 00:53:36.760 --> 00:53:40.440 They diverge from each other and stand at first nearly upright. 865 00:53:41.039 --> 00:53:44.199 When lightly rubbed on either side, they slowly bend to 866 00:53:44.360 --> 00:53:47.880 that side and subsequently become straight again. The back or 867 00:53:47.960 --> 00:53:51.320 convex side, when placed in contact with a stick, became 868 00:53:51.599 --> 00:53:54.880 just perceptibly curved in one hour twenty minutes, but did 869 00:53:54.920 --> 00:53:58.000 not completely surround it until forty eight hours had elapsed. 870 00:53:58.519 --> 00:54:02.000 The concave side of another became considerably curved in two 871 00:54:02.079 --> 00:54:05.519 hours and clasp a stick in five hours. As the 872 00:54:05.599 --> 00:54:08.800 pairs of tendrils grow old, one tendril divert is more 873 00:54:08.920 --> 00:54:11.960 and more from the other, and both slowly bend backwards 874 00:54:12.039 --> 00:54:14.800 and downwards, so that after a time they project on 875 00:54:14.880 --> 00:54:18.079 opposite sides of the stem to that from which they arise. 876 00:54:18.360 --> 00:54:21.920 They then still retain their sensitiveness and can clasp support 877 00:54:22.039 --> 00:54:26.239 placed behind the stem. Owing to this power, the plant 878 00:54:26.320 --> 00:54:30.360 is able to ascend a thin upright stick. Ultimately, the 879 00:54:30.440 --> 00:54:32.880 two tendrils belonging to the same pedule, if they do 880 00:54:33.000 --> 00:54:36.360 not come into contact with any other object, loosely cross 881 00:54:36.440 --> 00:54:40.199 each other behind the stem, as at b in Fig. Seven. 882 00:54:41.079 --> 00:54:43.639 This movement of the tendril towards and round the stem 883 00:54:43.920 --> 00:54:46.719 is to a certain extent guided by their avoidance of 884 00:54:46.800 --> 00:54:49.239 the light. For when a plant stood so that one 885 00:54:49.280 --> 00:54:52.320 of the two tendrils was compelled in thus slowly moving 886 00:54:52.679 --> 00:54:55.679 to travel towards the light, and the other from the light, 887 00:54:56.079 --> 00:54:59.719 the latter always moved, as I repeatedly observed, more quickly 888 00:54:59.760 --> 00:55:04.480 than fellow. The tendrils do not contract spirally. In any case, 889 00:55:05.039 --> 00:55:07.239 their chance of finding the support depends on the growth 890 00:55:07.320 --> 00:55:09.800 of the plant on the wind, and on their own 891 00:55:10.000 --> 00:55:13.760 slow backward and downward movement, which, as we have just seen, 892 00:55:14.280 --> 00:55:16.679 is guided to a certain extent by the avoidance of 893 00:55:16.760 --> 00:55:20.000 the light, for neither the internodes nor the tendrils have 894 00:55:20.119 --> 00:55:24.159 any proper revolving movement. From this latter circumstance. From the 895 00:55:24.400 --> 00:55:28.480 slow movements of the tendrils after contact, though their sensitiveness 896 00:55:28.599 --> 00:55:31.599 is retained for an unusual length of time. From their 897 00:55:31.679 --> 00:55:34.920 simple structure and shortness, this plant is a less perfect 898 00:55:35.039 --> 00:55:38.280 climber than any other tendril bearing species observed by me. 899 00:55:39.000 --> 00:55:41.480 The plant, whilst young and only a few inches in 900 00:55:41.599 --> 00:55:45.000 light height, does not produce any tendrils, and considering that 901 00:55:45.079 --> 00:55:47.679 it grows to only about eight feet

in height, that 902 00:55:48.119 --> 00:55:51.360 the stem is zigzagged and is furnished as well as 903 00:55:51.559 --> 00:55:55.119 the petioles with spines, it is surprising that it should 904 00:55:55.159 --> 00:56:00.599 be provided with tendrils comparatively inefficient. Though these are the 905 00:56:00.679 --> 00:56:03.239 plants might have been left, one would have thought to 906 00:56:03.320 --> 00:56:06.599 climb by the aid of its spines alone, like our brambles. 907 00:56:07.199 --> 00:56:09.760 As however, it belongs to a genus, some of the 908 00:56:09.800 --> 00:56:13.119 species of which are furnished with much longer tendrils, we 909 00:56:13.199 --> 00:56:16.079 may suspect that it possesses these organs solely from being 910 00:56:16.159 --> 00:56:22.079 descended from progenitors more highly organized. In this respect, Thumereacia 911 00:56:22.639 --> 00:56:27.840 cordialis claviculata. According to Mole, page forty three, the extremities 912 00:56:27.920 --> 00:56:30.239 of the branched stem as well as the leaves are 913 00:56:30.320 --> 00:56:34.320 converted into tendrils. In the specimens examined by me, all 914 00:56:34.360 --> 00:56:37.679 the tendrils were certainly folier, and it is hardly credible 915 00:56:37.760 --> 00:56:40.480 that the same plant should produce tendrils of a widely 916 00:56:40.599 --> 00:56:44.679 different homological nature. Nevertheless, from this statement by Mole, I 917 00:56:44.800 --> 00:56:49.079 have ranked this species amongst the tendril bearers. If classed 918 00:56:49.119 --> 00:56:52.639 exclusively by its folier tendrils, it would be doubtful whether 919 00:56:52.679 --> 00:56:55.679 it ought not to have been placed amongst the leaf climbers, 920 00:56:55.719 --> 00:57:01.360 with its allies Grumeria and Adulamia. A large majority of 921 00:57:01.480 --> 00:57:05.440 its so called tendrils still bear leaflets, though excessively reduced 922 00:57:05.519 --> 00:57:08.519 in size, but some few of them may properly be 923 00:57:08.639 --> 00:57:12.519 designated as tendrils, for they are completely destitute of lemonae 924 00:57:12.800 --> 00:57:16.800 or blades. Consequently, we here pull the plant in an 925 00:57:16.840 --> 00:57:19.239 actual state of transition from a leaf climbate to a 926 00:57:19.320 --> 00:57:23.039 tendril bearer. Whilst the plant is rather young, only the 927 00:57:23.159 --> 00:57:26.000 outer leaves, but when full grown all the leaves have 928 00:57:26.280 --> 00:57:30.079 their extremities converted into more or less perfect tendrils. I 929 00:57:30.239 --> 00:57:34.840 have examined species from one locality alone, viz. Hampshire, and 930 00:57:35.000 --> 00:57:38.280 it is not improbable that plants growing under different conditions 931 00:57:38.400 --> 00:57:40.920 might have their leaves a little more or less changed 932 00:57:41.119 --> 00:57:45.519 into true tendrils Whilst the plant is young. The first 933 00:57:45.599 --> 00:57:48.719 form leaves are not modified in any way, but those 934 00:57:48.920 --> 00:57:52.360 next formed have their terminal leaflets reduced in size, and 935 00:57:52.559 --> 00:57:55.440 soon all the leaves. Assume that the structure represented in 936 00:57:55.519 --> 00:57:59.559 the following drawing. This leaf bore nine leaflets, the lower 937 00:57:59.599 --> 00:58:03.639 ones being much subdivided. The terminal portion of the petule 938 00:58:03.679 --> 00:58:06.760 about one and one half inchine length above the leaflet 939 00:58:07.039 --> 00:58:10.159 f is thinner and more elongated than the lower part, 940 00:58:10.280 --> 00:58:13.920 and may be considered as the tendril. The leaflets borne 941 00:58:13.960 --> 00:58:17.239 by this part are greatly reduced in size, being on 942 00:58:17.440 --> 00:58:20.400 an average about the tenth of an inchine length and 943 00:58:20.599 --> 00:58:24.679 very narrow. One small leaflet measured one twelfth of an 944 00:58:24.760 --> 00:58:28.639 inchine length and one seventy fifth in breadth two point 945 00:58:28.760 --> 00:58:32.519 one one six millimeters and zero point three three nine millimeters, 946 00:58:32.920 --> 00:58:37.280 so that it was almost microscopically minute. All the reduced 947 00:58:37.360 --> 00:58:41.320 leaflets have branching nerves and terminate in little spines like 948 00:58:41.440 --> 00:58:45.440 those of the fully developed leaflets. Every gradation could be 949 00:58:45.599 --> 00:58:49.079 traced until we come to branchlets as A and D 950 00:58:49.400 --> 00:58:52.360 in the figure, which show no vestige of a lamina 951 00:58:52.480 --> 00:58:56.159 or blade. Occasionally, all the terminal branchlets of the petiole 952 00:58:56.199 --> 00:59:00.280 are in this condition, and we have a trutendril. The 953 00:59:00.360 --> 00:59:03.400 several terminal branches of the petiole bearing the much reduced 954 00:59:03.480 --> 00:59:07.360 leaflets A, D, C, D are highly sensitive. For a 955 00:59:07.440 --> 00:59:10.280 loop of thread weighing only one sixteenth of a grain 956 00:59:10.639 --> 00:59:14.119 four point zero five milligrams caused them to become greatly 957 00:59:14.239 --> 00:59:18.039 curved in under four hours. When the loop was removed, 958 00:59:18.079 --> 00:59:21.559 the petioles straightened themselves in about the same time. The 959 00:59:21.639 --> 00:59:25.719 petiole e was rather less sensitive, and in another specimen 960 00:59:25.880 --> 00:59:30.239 in which the corresponding petiole bore rather larger leaflets, a 961 00:59:30.320 --> 00:59:32.679 loop of thread weighing one eighth of a grain did 962 00:59:32.760 --> 00:59:36.800 not cause any curvature until eighteen hours had elapsed. Loops 963 00:59:36.840 --> 00:59:39.519 of thread weighing one fourth of a grain left suspended 964 00:59:39.599 --> 00:59:43.079 on the lower petules F to L during several days 965 00:59:43.159 --> 00:59:46.519 produced no effect. Yet, the three petioles F, G and 966

00:59:46.840 --> 00:59:50.679 H were not quite insensible, for when left in contact 967 00:59:50.760 --> 00:59:53.320 with a stick for a day or two, they slowly 968 00:59:53.400 --> 00:59:57.920 curled round it. Thus the sensibility of the petiole gradually 969 00:59:58.000 --> 01:00:01.280 diminishes from the tendril like extremity to the base. The 970 01:00:01.400 --> 01:00:04.199 internodes of the stem are not at all sensitive, which 971 01:00:04.280 --> 01:00:07.400 makes most statement that they are sometimes converted into tendrils 972 01:00:07.440 --> 01:00:11.760 the more surprising, not to say improbable. The whole leaf, 973 01:00:11.840 --> 01:00:15.000 whilst young and sensitive, stands almost vertically upwards, as we 974 01:00:15.079 --> 01:00:17.760 have seen to be the case with many tendrils. It 975 01:00:18.000 --> 01:00:20.679 is in a continual movement, and one that I observe 976 01:00:20.760 --> 01:00:24.519 swept an average rate of two hours for each revolution, 977 01:00:25.239 --> 01:00:29.320 large through irregular ellipses, which were sometimes narrow, sometimes broad, 978 01:00:29.360 --> 01:00:33.079 with their longer axes directed to different points of the compass. 979 01:00:33.920 --> 01:00:38.159 The young internodes likewise revolved irregularly in ellipses or spires, 980 01:00:38.440 --> 01:00:41.679 so that by these combined movements a considerable space was 981 01:00:41.719 --> 01:00:45.599 swept for a support. If the terminal or attenuated portion 982 01:00:45.719 --> 01:00:48.760 of perpetual fails to seize an object, it ultimately bends 983 01:00:48.800 --> 01:00:52.840 downwards and inwards, and soon loses all irritability and power 984 01:00:52.880 --> 01:00:56.360 of movement. This bending down dufers much in nature from 985 01:00:56.440 --> 01:00:59.280 that which occurs with the extremities of the young leaves 986 01:00:59.360 --> 01:01:02.559 in many speed is of comatus, for these, when thus 987 01:01:02.639 --> 01:01:06.599 bent downwards or hooked, first acquire their full debris of 988 01:01:06.719 --> 01:01:14.280 sensitiveness Dicentra phallic trifolia. In this allied plant, metamorphosis of 989 01:01:14.400 --> 01:01:17.800 the terminal leaflets is complete, and they are converted into 990 01:01:17.920 --> 01:01:21.639 perfect tendrils. Whilst the plant is young, the tendrils appear 991 01:01:21.840 --> 01:01:25.239 like modified branches, and a distinguished botanists thought that they 992 01:01:25.320 --> 01:01:28.199 were of this nature. But in a full grown plant 993 01:01:28.239 --> 01:01:30.679 there can be no doubt, as I am assured by 994 01:01:30.760 --> 01:01:34.679 doctor Hooker, that they are modified leaves. When a full 995 01:01:34.800 --> 01:01:38.119 size they are above five inches in length, they bifurcate twice, 996 01:01:38.239 --> 01:01:42.880 three thrice, or even four times. Their extremities are hooked 997 01:01:42.920 --> 01:01:46.280 and blunt. All the branches of the tendrils are sensitive 998 01:01:46.400 --> 01:01:48.840 on all sides, but the basal portion of the main 999 01:01:48.920 --> 01:01:53.039 stem is only slightly so. The terminal branches, when lightly 1000 01:01:53.159 --> 01:01:55.840 rubbed with a twig, became curved in the course of 1001 01:01:56.000 --> 01:02:00.960 from thirty minutes to forty two minutes, and straighten themselves 1002 01:02:01.079 --> 01:02:04.280 in between ten hours and twenty hours. A loop of 1003 01:02:04.480 --> 01:02:07.400 thread weighing one eighth of a grain plainly caused the 1004 01:02:07.480 --> 01:02:10.719 thinner branches to bend, as did occasionally a loop weigh 1005 01:02:10.719 --> 01:02:13.800 in one sixteenth of a grain, but this latter weight, 1006 01:02:13.960 --> 01:02:17.480 though left suspended, was not sufficient to cause a permanent flexure. 1007 01:02:18.199 --> 01:02:20.519 The whole leaf, with its tendril, as well as the 1008 01:02:20.679 --> 01:02:25.199 young upper internodes, revolves vigorously and quickly, though irregularly, and 1009 01:02:25.360 --> 01:02:28.679 thus sweeps a wide space. The figure traced on a 1010 01:02:28.760 --> 01:02:31.599 bell glass was either an irregular spire or a zig 1011 01:02:31.719 --> 01:02:35.039 zag lie. The nearest approach to an ellipse was an 1012 01:02:35.119 --> 01:02:38.519 elongated figure of eight with one end a little open, 1013 01:02:38.960 --> 01:02:41.719 and this was completed in one hour fifty three minutes. 1014 01:02:42.480 --> 01:02:45.440 During a period of six hours seventeen minutes, another shoot 1015 01:02:45.559 --> 01:02:49.639 made a complex figure, apparently representing three and a half ellipses. 1016 01:02:50.280 --> 01:02:52.760 When the lower part of the petule bearing the leaflets 1017 01:02:52.840 --> 01:02:56.360 was securely fastened. The tendril itself described similar but much 1018 01:02:56.400 --> 01:03:01.719 smaller figures. These species climb well. The tendrils, after clasping 1019 01:03:01.760 --> 01:03:04.599 a stick become thicker and more rigid, but the blunt 1020 01:03:04.639 --> 01:03:08.159 hooks do not turn and adapt themselves to the supporting surface, 1021 01:03:08.480 --> 01:03:10.800 as is done in so perfect a manner by some 1022 01:03:10.920 --> 01:03:16.000 Bignonacia and Cobain. The tendrils of young plants two or 1023 01:03:16.119 --> 01:03:18.719 three feet in height are only half the length of 1024 01:03:18.800 --> 01:03:21.559 those borne by the same plant when grown taller, and 1025 01:03:21.679 --> 01:03:24.800 they do not contract spirally after classing a support, but 1026 01:03:24.960 --> 01:03:29.480 only become slightly flexuous. Full Signe's tendrils, on the other hand, 1027 01:03:29.599 --> 01:03:32.960 contract spirally with the exception of the thick basal portion. 1028 01:03:33.960 --> 01:03:37.440 Tendrils which have caught nothing simply bend downwards and inwards, 1029 01:03:37.800 --> 01:03:41.079 like the extremity of the leaves of the Corydalis claviculata. 1030 01:03:41.800 --> 01:03:44.360 But in all cases the petule after a time is 1031 01:03:44.480 --> 01:03:48.920 angularly and abruptly bent downwards, like that of the echromocarpos 1032 01:03:49.360 --> 01:03:51.199 end of Chapter three.