Transcription complète de Chapter 2

one turn 32 00:02:30.120 --> 00:02:33.360 and a half, it ascended for a short space straight, 33 00:02:33.879 --> 00:02:37.319 then reversed its course and wound two turns in an 34 00:02:37.400 --> 00:02:41.879 opposite direction. This was rendered possible by the straight piece 35 00:02:42.039 --> 00:02:47.719 between the opposed spires having become rigid. The simple broad 36 00:02:47.840 --> 00:02:53.159 ovate leaves of this tropical species, with their short, thick petioles, 37 00:02:53.439 --> 00:02:57.439 seem but ill fitted for any movement, and whilst twining 38 00:02:57.560 --> 00:03:02.520 up a vertical stick, no use is made of them. Nevertheless, 39 00:03:02.560 --> 00:03:05.400 if the footstock of a young leaf be rubbed with 40 00:03:05.599 --> 00:03:09.599 a thin twig a few times on any side, it will, 41 00:03:09.719 --> 00:03:13.199 in the course of a few hours, bend to that side, 42 00:03:13.560 --> 00:03:18.479 afterwards becoming straight again. The underside seemed to be the 43 00:03:18.479 --> 00:03:23.520 most sensitive, but the sensitiveness or irritability is slight compared 44 00:03:23.639 --> 00:03:26.280 to that which we shall meet with in some of 45 00:03:26.319 --> 00:03:31.039 the following species. Thus, a loop of string weighing one 46 00:03:31.080 --> 00:03:35.240 point six four grain one hundred and six point two milligram, 47 00:03:35.800 --> 00:03:39.319 and hanging for some days on a young footstock produced 48 00:03:39.400 --> 00:03:43.719 a scarcely perceptible effect. A sketch is yere given of 49 00:03:43.879 --> 00:03:47.479 two young leaves which had naturally caught hold of two 50 00:03:47.639 --> 00:03:51.680 thin branches. A forked twig placed so as to press 51 00:03:51.759 --> 00:03:55.680 lightly on the underside of a young footstock caused it 52 00:03:55.840 --> 00:03:59.840 in twelve hours to bend, flossing, and ultimately to set 53 00:03:59.879 --> 00:04:03.439 an extent that the leaf passed to the opposite side 54 00:04:03.439 --> 00:04:07.159 of the stem. The fork stick having been removed, the 55 00:04:07.240 --> 00:04:13.520 leaf slowly recovered its former position. The young leaves spontaneously 56 00:04:13.599 --> 00:04:18.439 and gradually change their position. When first developed, the petioles 57 00:04:18.480 --> 00:04:22.399 are upturned and parallel to the stem. They then slowly 58 00:04:22.480 --> 00:04:26.800 bend downwards, remaining for a short time at right angles 59 00:04:26.839 --> 00:04:30.680 to the stem, and then becomes so much arched downwards 60 00:04:30.920 --> 00:04:33.639 that the blade of the leaf points to the ground, 61 00:04:33.720 --> 00:04:37.279 with its tip curled inwards, so that the whole petiole 62 00:04:37.399 --> 00:04:41.480 and leaf together form a hook. They are thus enabled 63 00:04:41.519 --> 00:04:44.600 to catch hold of any twig with which they may 64 00:04:44.639 --> 00:04:48.839 be brought into contact by the revolving movement of the internodes. 65

00:04:49.560 --> 00:04:52.879 If this does not happen, they retain their hook shape 66 00:04:52.959 --> 00:04:57.560 for considerable times, and then, bending upwards, reassume their original 67 00:04:57.680 --> 00:05:03.000 upturned position, which is preserved ever afterwards. The petioles, which 68 00:05:03.040 --> 00:05:07.759 have clasped any object, soon become much thickened and strengthened, 69 00:05:08.040 --> 00:05:13.199 as may be seen in the drying Clematis montana. The long, 70 00:05:13.360 --> 00:05:17.480 thin petioles of the leaves, whilst young, are sensitive, and 71 00:05:17.519 --> 00:05:22.040 when lightly rubbed, bend to the rubbed side, subsequently becoming straight. 72 00:05:22.639 --> 00:05:27.079 They are far more sensitive than the petioles of sea glandulosa. 73 00:05:27.600 --> 00:05:29.959 For a loop of thread weighing a quarter of a 74 00:05:30.079 --> 00:05:34.920 grain sixteen point two milligrams caused them to bend. A 75 00:05:35.000 --> 00:05:39.319 loop weighing only one eighth miligrain eight point one milligrams 76 00:05:39.360 --> 00:05:44.839 sometimes acted and sometimes did not. The sensitiveness extends from 77 00:05:44.839 --> 00:05:47.639 the blade of the leaf to the stem. I may 78 00:05:47.680 --> 00:05:51.160 here state that I ascertained in all cases the weights 79 00:05:51.199 --> 00:05:55.000 of the string and thread used by carefully weighing fifteen 80 00:05:55.000 --> 00:05:59.240 inches in a chemical balance and then cutting off measured lengths. 81 00:06:00.079 --> 00:06:04.879 The main petiole carries three leaflets, but their short subpetioles 82 00:06:04.959 --> 00:06:09.639 are not sensitive. A young inclined shoot the plant, being 83 00:06:09.720 --> 00:06:13.199 in the greenhouse, made a large circle opposed to the 84 00:06:13.240 --> 00:06:16.879 course of the sun in four hours twenty minutes, but 85 00:06:17.000 --> 00:06:20.360 the next day, being very cold, the time was five 86 00:06:20.399 --> 00:06:24.560 hours ten minutes. A stick placed near a revolving stem 87 00:06:24.879 --> 00:06:28.120 was soon struck by the petioles, which stand out at 88 00:06:28.199 --> 00:06:32.920 right angles, and the revolving movement was thus arrested. The 89 00:06:33.000 --> 00:06:37.399 petioles then began, being excited by the contact, to slowly 90 00:06:37.519 --> 00:06:41.199 wind around the stick. When the stick was thin, a 91 00:06:41.279 --> 00:06:45.959 petiole sometimes wound twice around it. The opposite leaf was 92 00:06:46.000 --> 00:06:50.560 in no way effected. The attitude assumed by the stem 93 00:06:50.800 --> 00:06:54.040 after the petiole had clasped the stick was that of 94 00:06:54.040 --> 00:06:58.000 a man standing by column who throws his arm horizontally 95 00:06:58.079 --> 00:07:02.720 around it. With respect the stem's power of twining, some 96 00:07:02.920 --> 00:07:09.120 remarks will be made. Under Sea Calucina Clematus cyboldi, a 97 00:07:09.199 --> 00:07:12.759 shoot made three revolutions against the sun at an average 98 00:07:12.839 --> 00:07:16.439 rate of three hours eleven minutes. The power of twining 99 00:07:16.560 --> 00:07:20.279 is like that of the last species. Its leaves are 100 00:07:20.360 --> 00:07:24.800 nearly similar instruction and in function, excepting that the suber 101 00:07:24.879 --> 00:07:29.519 petioles of the lateral and terminal leaflets are sensitive. A 102 00:07:29.560 --> 00:07:32.920 loop of thread away one eighth of a grain acted 103 00:07:33.079 --> 00:07:36.399 on the main petiole, but not until two or three 104 00:07:36.480 --> 00:07:40.199 days had elapsed. The leaves have the remarkable habit of 105 00:07:40.279 --> 00:07:45.120 spontaneously revolving generally in vertical ellipses in the same manner, 106 00:07:45.439 --> 00:07:48.439 but in a less degree, as will be described under 107 00:07:48.480 --> 00:07:55.839 sea Microphilia Clematis calusina. The young shoots are thin and flexible. 108 00:07:56.319 --> 00:08:00.959 One revolve describing a broad oval in five hours thirty minutes, 109 00:08:01.360 --> 00:08:05.120 and another in six hours twelve minutes. They followed the 110 00:08:05.160 --> 00:08:08.480 course of the sun, but the course, if observed long enough, 111 00:08:08.680 --> 00:08:12.199 would probably be found to vary in this species as 112 00:08:12.240 --> 00:08:15.360 well as in all others of the genus. It is 113 00:08:15.399 --> 00:08:19.120 a rather better twiner than the last two species. The 114 00:08:19.160 --> 00:08:23.279 stems sometimes made two spiral turned mound a thin stick. 115 00:08:23.519 --> 00:08:26.879 If free from twigs. It then ran straight up for 116 00:08:26.920 --> 00:08:29.879 a space and reversed in its course took one or 117 00:08:29.920 --> 00:08:34.080 two turns in an opposite direction. This reversal of the 118 00:08:34.159 --> 00:08:39.039 spire occurred in all the foregoing species. The leaves are 119 00:08:39.120 --> 00:08:42.320 so small compared with those of most of the other 120 00:08:42.440 --> 00:08:48.480 species that the petioles at first seem ill adapted for clasping. Nevertheless, 121 00:08:48.600 --> 00:08:51.519 the main service of the revolving movement is to bring 122 00:08:51.559 --> 00:08:55.240 them into contact with surrounding objects, which are slowly but 123 00:08:55.600 --> 00:09:00.679 securely seized. The young petioles, which alone are sensible, have 124 00:09:00.879 --> 00:09:04.120 their ends bowed a little downwards so as to be 125 00:09:04.320 --> 00:09:08.919 an a slight degree hooked. Ultimately, the whole leaf, if 126 00:09:08.919 --> 00:09:12.919 it catches nothing, becomes level. I gently rubbed with a 127 00:09:12.960 --> 00:09:17.039 thin twig the lower surfaces of two young petioles, and 128 00:09:17.159 --> 00:09:20.840 in two hours thirty minutes they were slightly curved downwards. 129 00:09:21.360 --> 00:09:24.639 In five hours after being rubbed, the end of one 130

00:09:24.960 --> 00:09:29.559 was bent completely back parallel to the basal portion. In 131 00:09:29.679 --> 00:09:34.039 four hours. Subsequently it became nearly straight again. To show 132 00:09:34.120 --> 00:09:37.639 how sensitive the young petioles are, I may mention that 133 00:09:37.720 --> 00:09:42.679 I just touched the undersides of two with a little watercolor, which, 134 00:09:42.720 --> 00:09:46.799 when dry, formed an excessively thin and minute crust. But 135 00:09:46.879 --> 00:09:49.759 this sufficed in twenty four hours to cause both to 136 00:09:49.799 --> 00:09:54.840 bend downwards. Whilst the plant is young, each leaf consists 137 00:09:54.919 --> 00:09:59.399 of three divided leaflets, which barely have distinct petioles, and 138 00:09:59.480 --> 00:10:03.120 these are sensitive. But when the plant is well grown, 139 00:10:03.440 --> 00:10:06.840 the petioles of the two lateral and terminal leaflets are 140 00:10:06.960 --> 00:10:10.720 of considerable length, and becomes sensitive so as to be 141 00:10:10.799 --> 00:10:16.000 capable of clasping an object in any direction. When a 142 00:10:16.039 --> 00:10:20.240 petiole has clasped a twig, it undergoes some remarkable changes 143 00:10:20.600 --> 00:10:24.000 which may be observed with the other species, but in 144 00:10:24.039 --> 00:10:27.759 a less strongly marked manner, and will here be described 145 00:10:27.879 --> 00:10:31.320 once for all. The clasped petiole, in the course of 146 00:10:31.360 --> 00:10:35.200 two or three days, swells greatly and ultimately becomes nearly 147 00:10:35.240 --> 00:10:39.679 twice as thick as the opposite one, which has clasped nothing. 148 00:10:40.600 --> 00:10:44.039 When thin transverse slices of the two are placed under 149 00:10:44.039 --> 00:10:48.200 the microscope. Their difference is conspicuous. The side of the 150 00:10:48.240 --> 00:10:51.000 petiole which has been in contact with the support is 151 00:10:51.080 --> 00:10:54.320 formed of a layer of colorless cells with their longer 152 00:10:54.440 --> 00:10:58.399 axis directed from the center, and these are very much 153 00:10:58.480 --> 00:11:02.679 larger than the corresponding cells in the opposite or unchanged petiole. 154 00:11:03.600 --> 00:11:07.320 The central cells also are in some degree enlarged, and 155 00:11:07.360 --> 00:11:12.399 the whole is much indurated. The exterior surface generally becomes 156 00:11:12.480 --> 00:11:16.440 bright red, but a far greater change takes place in 157 00:11:16.480 --> 00:11:19.480 the nature of the tissues than that which is visible. 158 00:11:20.039 --> 00:11:23.279 The petule of the unclasped leaf is flexible and can 159 00:11:23.320 --> 00:11:28.120 be snapped easily, whereas the clasped one acquires an extraordinary 160 00:11:28.120 --> 00:11:32.399 degree of toughness and rigidity, so that considerable force is 161 00:11:32.440 --> 00:11:36.600 required to pull it into pieces. With this change, great 162 00:11:36.679 --> 00:11:41.039 durability is probably acquired. At least this is the case 163 00:11:41.120 --> 00:11:46.279 with the clasped petioles of Pitalba. The meaning of these 164 00:11:46.360 --> 00:11:50.480 changes is obvious, namely that the petioles may firmly and 165 00:11:50.600 --> 00:11:58.240 durably support the stem clematis microphilia variation leptophilia. The long 166 00:11:58.440 --> 00:12:03.080 and thin internodes of this Australian species revolves sometimes in 167 00:12:03.120 --> 00:12:07.600 one direction and sometimes in an opposite one, describing long, narrow, 168 00:12:07.679 --> 00:12:13.120 irregular ellipses, or large circles. Four revolutions were completed within 169 00:12:13.360 --> 00:12:16.720 five minutes of the same average rate of one hour 170 00:12:16.799 --> 00:12:20.879 fifty one minutes, so that this species moves more quickly 171 00:12:21.159 --> 00:12:24.960 than the others of the genus. The shoots, when placed 172 00:12:25.039 --> 00:12:28.679 near a vertical stick, either twine round or clasp it 173 00:12:29.080 --> 00:12:33.919 with the basal portions of their petioles. The leaves, whilst young, 174 00:12:34.200 --> 00:12:36.639 are nearly of the same shape as those of the 175 00:12:36.679 --> 00:12:40.720 sea Viticella, and act in the same manner like a hook, 176 00:12:41.039 --> 00:12:45.039 as will be described under that species, but the leaflets 177 00:12:45.080 --> 00:12:48.960 are more divided, and each segment whilst young, terminates in 178 00:12:49.120 --> 00:12:53.240 a hardish point which is much curved downwards and inwards, 179 00:12:53.559 --> 00:12:56.559 so that the whole leaf readily catches hold of any 180 00:12:56.600 --> 00:13:01.559 neighboring object. The petibles of the young terminal leaflets are 181 00:13:01.600 --> 00:13:05.080 acted on by loops of thread weighing one eighth and 182 00:13:05.200 --> 00:13:09.440 even zero point zero six two fifth of a grain. 183 00:13:09.720 --> 00:13:13.200 The basal portion of the main petule is much less sensitive, 184 00:13:13.600 --> 00:13:18.000 but will clasp a stick against which it presses. The leaves, 185 00:13:18.120 --> 00:13:23.440 whilst young, are continually and spontaneously moving slowly. A bell 186 00:13:23.519 --> 00:13:26.480 glass was placed over a shoot secured to a stick, 187 00:13:26.879 --> 00:13:29.399 and the movements of the leaves were traced on it. 188 00:13:29.559 --> 00:13:34.200 During several days. A very irregular line was generally formed, 189 00:13:34.720 --> 00:13:37.759 but one day, in the course of eight hours and 190 00:13:38.120 --> 00:13:42.480 three quarters the figure clearly represented three and a half 191 00:13:43.039 --> 00:13:47.279 irregular ellipses, the most perfect one of which was completed 192 00:13:47.360 --> 00:13:52.039 in two hours thirty five minutes. The two opposite leaves 193 00:13:52.080 --> 00:13:56.159 moved independently of each other. This movement of the leaves 194

00:13:56.200 --> 00:13:59.480 would aid that of the internodes in bringing the petioles 195 00:13:59.519 --> 00:14:04.080 into cons with surrounding objects. I discovered this movement too 196 00:14:04.240 --> 00:14:07.720 late to be enabled to observe it in the other species, 197 00:14:08.240 --> 00:14:11.440 but from analogy I can hardly doubt that the leaves 198 00:14:11.480 --> 00:14:16.519 of at least SEE. Vitcella, C. Flamula and C. Vitalba 199 00:14:16.840 --> 00:14:21.960 move spontaneously, and judging from C. Cyboldi, this probably is 200 00:14:22.000 --> 00:14:26.559 the case with the C. Montana and C. Calisina, I 201 00:14:26.639 --> 00:14:31.480 ascertained that these simple leaves of C. Glandulosa exhibit no 202 00:14:31.679 --> 00:14:39.919 spontaneous revolving movement. Clematis viticella variation Venosa in this and 203 00:14:40.000 --> 00:14:43.600 the two falling species, the power of spirally twining is 204 00:14:43.679 --> 00:14:47.679 completely lost, and this seems due to the lessened flexibility 205 00:14:47.720 --> 00:14:50.320 of the internodes and to the interface caused by the 206 00:14:50.440 --> 00:14:55.200 large size of the leaves. But the revolving movement, though restricted, 207 00:14:55.399 --> 00:14:59.639 is not lost in our present species. A young internode 208 00:14:59.720 --> 00:15:02.960 plays in the front of a window made three narrow 209 00:15:03.080 --> 00:15:07.080 ellipses transversely to the direction of the light at an 210 00:15:07.120 --> 00:15:11.159 average rate of two hours forty minutes. When placed so 211 00:15:11.200 --> 00:15:13.759 that the movements were to and from the light, the 212 00:15:13.840 --> 00:15:17.000 rate was greatly accelerated in one half of the course 213 00:15:17.320 --> 00:15:21.279 and retarded in the other. As with twining plants, the 214 00:15:21.320 --> 00:15:25.559 ellipses were small. The longer diameter described by the apex 215 00:15:25.639 --> 00:15:28.720 of a shoot bearing a pair of not expanded leaves 216 00:15:29.080 --> 00:15:32.559 was only four or five eighths inches, and that by 217 00:15:32.559 --> 00:15:35.840 the apex of the penultimate internode was only one one 218 00:15:35.960 --> 00:15:40.240 eighth inch. At the most favorable period of growth, each 219 00:15:40.360 --> 00:15:43.320 leaf would hardly be carried to and fro by the 220 00:15:43.360 --> 00:15:46.919 movement of the internodes more than two or three inches, 221 00:15:47.519 --> 00:15:51.320 But as stated above, it is probable that leaves themselves 222 00:15:51.639 --> 00:15:55.480 moved spontaneously. The movement of the whole shoot by the 223 00:15:55.519 --> 00:15:59.559 wind and by its rapid growth, would probably be almost 224 00:15:59.639 --> 00:16:04.440 equal efficient as these spontaneous movements in bringing the petioles 225 00:16:04.480 --> 00:16:09.519 into contact with surrounding objects. The leaves are of large size. 226 00:16:09.960 --> 00:16:14.080 Each bears three

pairs of lateral leaflets and a terminal one, 227 00:16:14.519 --> 00:16:19.759 all supported on rather long subpetioles. The main petiole bends 228 00:16:19.799 --> 00:16:23.679 a little angularly downwards at each point where a pair 229 00:16:23.759 --> 00:16:28.120 of leaflets arises see Figure two, and the petiole of 230 00:16:28.159 --> 00:16:32.559 the terminal leaflet is bent downwards at right angles. Hence, 231 00:16:32.600 --> 00:16:37.320 the whole petiole, with its rectangularly bent extremity, acts as 232 00:16:37.320 --> 00:16:41.519 a hook. This hook, the lateral petoles, being directed a 233 00:16:41.519 --> 00:16:46.360 little upwards, forms an excellent grappling apparatus by which the 234 00:16:46.440 --> 00:16:52.000 leaves readily become entangled with surrounding objects. If they catch nothing, 235 00:16:52.120 --> 00:16:58.039 the whole petiole ultimately grows straight. The main petiole, the subpetioles, 236 00:16:58.399 --> 00:17:02.879 and the three branches into which each basilateral subpetiole is 237 00:17:03.000 --> 00:17:08.240 generally subdivided, are all sensitive. The basal portion of the 238 00:17:08.279 --> 00:17:11.359 main petiole between the stem and the first pair of 239 00:17:11.440 --> 00:17:16.240 leaflets is less sensitive than the remainder. It will, however, 240 00:17:16.440 --> 00:17:19.720 clasp a stick with which it is left in contact. 241 00:17:20.400 --> 00:17:25.599 The inferior surface of the rectangularly bent terminal portion carrying 242 00:17:25.720 --> 00:17:29.279 the terminal leaflet, which forms the inner side of the 243 00:17:29.440 --> 00:17:33.039 end of the hook, is the most sensitive part, and 244 00:17:33.160 --> 00:17:37.880 this portion is manifestly best adapted to catch a distinct support. 245 00:17:38.880 --> 00:17:43.039 To show the difference in sensibility, I gently placed loops 246 00:17:43.039 --> 00:17:46.480 of string of the same weight, in one instance, laying 247 00:17:46.519 --> 00:17:50.119 only zero point eight two of a grain or fifty 248 00:17:50.119 --> 00:17:56.119 three point one four milligrams on the several lateral subpetioles 249 00:17:56.480 --> 00:17:59.759 and on the terminal one. In a few hours of 250 00:17:59.799 --> 00:18:02.599 the UAE the ladder was spent, but after twenty four 251 00:18:02.640 --> 00:18:08.519 hours no effect was produced on the other sub petioles. Again, 252 00:18:08.960 --> 00:18:12.359 a terminal subpetiole placed in contact with a thin stick 253 00:18:12.720 --> 00:18:16.759 becomes sensibly curved in forty five minutes and in one 254 00:18:16.799 --> 00:18:21.000 hour ten minutes moved through ninety degrees, whilst a lateral 255 00:18:21.079 --> 00:18:25.319 subpetiole did not become sensibly curved until three hours thirty 256 00:18:25.359 --> 00:18:29.519 minutes had elapsed. In all cases, if the sticks are 257 00:18:29.559 --> 00:18:34.000 taken away, the petioles continue to move during many hours afterwards, 258 00:18:34.440 --> 00:18:38.200 so they do after a slight rubbing, but they become 259 00:18:38.319 --> 00:18:42.440 straight again after about a day's interval, that is, if 260 00:18:42.559 --> 00:18:46.039 the fracture has not been very great or long continued. 261 00:18:47.359 --> 00:18:51.000 The graduated difference in the extension of the sensitiveness in 262 00:18:51.039 --> 00:18:56.519 the petioles of the above dementsen species deserves notice. In Sa. Montana, 263 00:18:56.799 --> 00:18:59.400 it is confined to the main petiole and has not 264 00:18:59.440 --> 00:19:02.559 spread to the sad subpetioles of the three leaflets. So 265 00:19:02.599 --> 00:19:06.319 it is with the young plants of Sea Calucina, but 266 00:19:06.440 --> 00:19:11.720 in older plants it spreads to the three subpetioles. In C. Viticella, 267 00:19:12.000 --> 00:19:15.000 the sensitiveness has spread to the petioles of the seven 268 00:19:15.039 --> 00:19:19.160 leaflets and to the subdivisions of the basal lateral sub petioles. 269 00:19:19.720 --> 00:19:22.559 But in this latter species it has diminished in the 270 00:19:22.599 --> 00:19:25.799 basal part of the main petiole, in which alone it 271 00:19:25.880 --> 00:19:30.039 resided in Sea Montana, whilst it has increased in the 272 00:19:30.119 --> 00:19:37.039 abruptly bent terminal position. Clematis flamula, the rather thick, straight 273 00:19:37.200 --> 00:19:41.000 and stiff shoots, whilst growing vigorously in the spring, make 274 00:19:41.119 --> 00:19:45.920 small oval revolutions following the sun in their course. Four 275 00:19:45.960 --> 00:19:48.759 were made at an average rate of three hours forty 276 00:19:48.799 --> 00:19:52.559 five minutes. The longer axis of the oval described by 277 00:19:52.559 --> 00:19:55.880 the extreme tip, was directed at right angles to the 278 00:19:55.960 --> 00:19:59.839 line joining the opposite leaves. Its length was in one 279 00:20:00.119 --> 00:20:03.799 case only one three eighths and in another case one 280 00:20:03.880 --> 00:20:07.880 three fourths inch, so that the young leaves were moved 281 00:20:08.000 --> 00:20:11.799 a very short distance. The shoots of the same plant, 282 00:20:11.920 --> 00:20:16.480 observed in midsummer, when growing not so quickly, did not 283 00:20:16.599 --> 00:20:20.279 revolve at all. I cut down another planet in the 284 00:20:20.319 --> 00:20:24.200 early summer, so that by August first it had formed 285 00:20:24.599 --> 00:20:28.960 new and moderately vigorous shoots. These, when observed under a 286 00:20:28.960 --> 00:20:32.839 bell glass, were on some days quite stationary, and on 287 00:20:32.960 --> 00:20:36.359 other days moved to and fro only about an eighth 288 00:20:36.440 --> 00:20:40.839 of an inch. Consequently, the revolving power is much enfeebled 289 00:20:40.960 --> 00:20:45.960 in this species, and under unfavorable circumstances, is completely lost. 290 00:20:46.720 --> 00:20:50.559 The shoot must depend

for coming into contact with surrounding objects, 291 00:20:50.839 --> 00:20:55.680 on the probable though not ascertained, spontaneous movement of the leaves, 292 00:20:55.720 --> 00:21:00.400 on rapid growth, and on movement from the wind. Hence, 293 00:21:00.440 --> 00:21:03.680 perhaps it is that the petioles have acquired a high 294 00:21:03.680 --> 00:21:08.000 degree of sensitiveness as a compensation for the little power 295 00:21:08.039 --> 00:21:12.559 of movement in the sheets. The petioles are bowed downwards 296 00:21:12.920 --> 00:21:15.839 and have the same general hook like form as in 297 00:21:15.960 --> 00:21:21.000 sea Viticella. The medial petiole and the lateral subpetioles are sensitive, 298 00:21:21.480 --> 00:21:26.240 especially the much bent terminal portion. As the sensitiveness is 299 00:21:26.279 --> 00:21:29.319 here greater than in any other species of the genus 300 00:21:29.359 --> 00:21:33.119 observed by me, and is in itself remarkable. I will 301 00:21:33.160 --> 00:21:37.240 give further details. The petioles, when so young that they 302 00:21:37.279 --> 00:21:41.319 have not separated from one another, are not sensitive. When 303 00:21:41.359 --> 00:21:44.720 the laminelle of a leaflet has grown to a quarter 304 00:21:44.880 --> 00:21:48.079 of an inch in length, that is about one sixth 305 00:21:48.160 --> 00:21:52.519 of its full size, the sensitiveness is highest. But at 306 00:21:52.519 --> 00:21:56.480 this period the petioles are read relatively much more fully 307 00:21:56.519 --> 00:22:00.519 developed than are the blades of the leaves. Low growned 308 00:22:00.559 --> 00:22:04.480 petioles are not in the least sensitive. A thin stick 309 00:22:04.559 --> 00:22:08.119 placed source to press lightly against a petiole having a 310 00:22:08.200 --> 00:22:11.559 leaflet a quarter of an ancient like caused the petule 311 00:22:11.640 --> 00:22:15.319 to bend in three hours fifteen minutes. In another case, 312 00:22:15.359 --> 00:22:18.680 a petiole curled completely round a stick in twelve hours. 313 00:22:19.359 --> 00:22:23.079 These petioles were left curled for twenty four hours, and 314 00:22:23.160 --> 00:22:26.920 the sticks were then removed, but they never straightened themselves. 315 00:22:27.720 --> 00:22:30.880 I took a twig thinner than the petiole itself, and 316 00:22:30.960 --> 00:22:36.000 with it lightly rubbed several petioles four times up and down. These, 317 00:22:36.160 --> 00:22:39.839 in one hour forty five minutes became slightly curled. The 318 00:22:39.880 --> 00:22:43.519 curvature increased during some hours and then began to decrease, 319 00:22:44.079 --> 00:22:47.039 but after twenty five hours from the time of rubbing, 320 00:22:47.359 --> 00:22:52.079 a vestige of the curvature remained. Some other petioles, similarly 321 00:22:52.160 --> 00:22:55.920 rubbed twice, that is, once up and once down, became 322 00:22:56.119 --> 00:23:00.880 perceptibly curved in about two hours thirty minutes, the terminal 323 00:23:00.920 --> 00:23:05.440 subpetiole moving more than the lateral subpetioles. They all became 324 00:23:05.519 --> 00:23:10.319 straight once again in between twelve hours and forteen hours. Lastly, 325 00:23:10.359 --> 00:23:12.920 a length of about one ach of an inch of 326 00:23:12.960 --> 00:23:17.000 a subpetiole was lightly rubbed with the same twig only once. 327 00:23:17.599 --> 00:23:21.759 It became slightly curved in three hours, remaining so during 328 00:23:21.799 --> 00:23:25.119 eleven hours, but by the next morning was quite straight. 329 00:23:26.319 --> 00:23:31.359 The following observations are more precise. After trying heavier pieces 330 00:23:31.400 --> 00:23:34.599 of string and thread, I placed a loop of fine 331 00:23:34.680 --> 00:23:39.480 string weighing one point zero four grain sixty seven point 332 00:23:39.559 --> 00:23:45.000 four milligrams on a terminal subpetiole In six hours forty 333 00:23:45.039 --> 00:23:48.599 minutes a curvature could be seen. In twenty four hours 334 00:23:48.599 --> 00:23:52.119 the petiole formed an open ring round the string. In 335 00:23:52.200 --> 00:23:55.079 forty eight hours the ring had almost closed on the string, 336 00:23:55.720 --> 00:23:59.440 and in seventy two hours seized it so firmly that 337 00:23:59.519 --> 00:24:04.279 some was necessary for its withdrawal. A loop weighing zero 338 00:24:04.400 --> 00:24:07.359 point five to two of a grain thirty three point 339 00:24:07.480 --> 00:24:12.759 seven milligrams caused in fourteen hours a lateral subpetule just 340 00:24:12.880 --> 00:24:16.640 perceptibly to curve, and in twenty four hours it moved 341 00:24:16.680 --> 00:24:20.680 through ninety degrees. These observations were made during the summer. 342 00:24:21.279 --> 00:24:23.920 The following were made in the spring, when the petioles 343 00:24:24.000 --> 00:24:27.880 apparently are more sensitive. A loop of thread weighing one 344 00:24:27.960 --> 00:24:31.599 eighth of a grain eight point one milligrams produced no 345 00:24:31.720 --> 00:24:35.720 effect on the lateral subpetules, but placed on a terminal 346 00:24:35.759 --> 00:24:39.640 one caused it, after twenty four hours to curve moderately. 347 00:24:40.480 --> 00:24:44.960 The curvature, though the loop remained suspended, was after forty 348 00:24:44.960 --> 00:24:49.200 eight hours diminished but never disappeared, showing that the petule 349 00:24:49.240 --> 00:24:54.640 had become partially accustomed to the insufficient stimulus. This experiment 350 00:24:54.880 --> 00:24:59.200 was twice repeated with nearly the same result. Lastly, a 351 00:24:59.240 --> 00:25:03.839 loop of thread weighing only one sixteenth of a gram 352 00:25:04.119 --> 00:25:08.920 four point zero five milligrams, was twice gently placed by 353 00:25:09.000 --> 00:25:13.720 a forcept on a terminal subpetiole, the plant being of 354 00:25:13.799 --> 00:25:18.160 course in a still

enclosed room, and this weight certainly 355 00:25:18.559 --> 00:25:22.839 caused a flexture which very slowly increased until the petrole 356 00:25:22.880 --> 00:25:26.920 moved through nearly ninety degrees. Beyond this, it did not move, 357 00:25:27.440 --> 00:25:31.799 nor did the petiole. The loop, remaining suspended, ever become 358 00:25:31.960 --> 00:25:36.599 perfectly straight. Again. When we consider, on the one hand, 359 00:25:36.720 --> 00:25:40.000 the thickness and stiffness of the petioles, and on the 360 00:25:40.039 --> 00:25:44.119 other the thinness and softness of a fine cotton thread, 361 00:25:44.240 --> 00:25:47.400 and what an extremely small weight one sixteenth of a 362 00:25:47.480 --> 00:25:53.039 grain four point zero five milligrams is, these facts are remarkable, 363 00:25:53.960 --> 00:25:56.839 but I have reason to believe that even a less 364 00:25:56.920 --> 00:26:01.400 weight excites curvature when pressing over a water surface than 365 00:26:01.440 --> 00:26:05.240 that acted on by a thread. Having noticed that the 366 00:26:05.400 --> 00:26:09.000 end of a suspended string which accidentally touched a petiole 367 00:26:09.160 --> 00:26:12.240 caused it to bend, I took two pieces of thin 368 00:26:12.319 --> 00:26:16.680 twine ten inches in length, weighing one point sixty four grain, 369 00:26:17.319 --> 00:26:20.160 and tying them to a stick let them hang as 370 00:26:20.240 --> 00:26:25.839 nearly perpendicularly downward as their thinness and flexiless form after 371 00:26:25.920 --> 00:26:30.119 being stretched would permit. I then quietly placed their ends 372 00:26:30.160 --> 00:26:34.359 so as to just rest on two petioles, and these 373 00:26:34.400 --> 00:26:38.279 certainly became curved. In thirty six hours, one of the 374 00:26:38.480 --> 00:26:42.240 ends touched the angle between a terminal and lateral subpetiole, 375 00:26:42.599 --> 00:26:45.559 and it was in forty eight hours caught between them 376 00:26:45.599 --> 00:26:49.680 as by a forceps. In these cases, the pressure, though 377 00:26:49.720 --> 00:26:52.559 spread over a wider surface than that touched by the 378 00:26:52.599 --> 00:26:58.640 cotton thread, must have been excessively slide clematis. The talba 379 00:26:59.599 --> 00:27:02.640 the plan pants were in pots and not healthy, so 380 00:27:02.680 --> 00:27:06.599 that I dare not trust my observations, which indicate much 381 00:27:06.640 --> 00:27:10.960 similarity in habits with the sea flamula. I mention this 382 00:27:11.039 --> 00:27:14.359 species only because I have seen many proofs that the 383 00:27:14.359 --> 00:27:17.759 peticles in a state of nature are excited to movement 384 00:27:17.880 --> 00:27:21.920 by very slight pressure. For instance, I have found them 385 00:27:21.960 --> 00:27:26.519 embracing thin, withered blades of grass, the soft young leaves 386 00:27:26.519 --> 00:27:30.119 of a maple, and the flower peduncles of the quaking 387 00:27:30.160 --> 00:27:34.599 grass or blizza. The latter are about as thick as 388 00:27:34.640 --> 00:27:38.279 the hair of a man's beard, but they are completely 389 00:27:38.319 --> 00:27:42.599 surrounded and clasped the petioles of a leaf so young 390 00:27:42.799 --> 00:27:46.160 that none of the leaflets were expanded, had partially seized 391 00:27:46.200 --> 00:27:50.880 a twig. Those of almost all the old leaves, even 392 00:27:50.920 --> 00:27:55.880 when unattached to any object, are much convoluted, but this 393 00:27:56.039 --> 00:27:59.519 is owing to their having come whilst young, into contact 394 00:27:59.640 --> 00:28:04.559 during several hours with some object subsequently removed. With none 395 00:28:04.599 --> 00:28:09.519 of the above described species cultivated in pots and carefully observed, 396 00:28:10.039 --> 00:28:13.400 was there any permanent bending of the petioles without the 397 00:28:13.440 --> 00:28:18.480 stimulus of contact. In winter, the blades of the leaves 398 00:28:18.480 --> 00:28:22.200 of Sea Vitalba drop off, but the petioles, as was 399 00:28:22.240 --> 00:28:26.400 observed by male, remain attached to the branches, sometimes during 400 00:28:26.440 --> 00:28:33.119 two seasons, and being convoluted, they curiously resemble true tendrils, 401 00:28:33.160 --> 00:28:37.759 such as those possessed by the allied genus narravealia. The 402 00:28:37.799 --> 00:28:42.079 petioles which have clasped some object become much more stiff, hard, 403 00:28:42.160 --> 00:28:45.480 and polished than those which have failed in this their 404 00:28:45.519 --> 00:28:59.160 proper function. Tropelium I observed T. Tricholorum, t Azurium, T. Pentaphyllum, T. Peregrinium, T. Elegans, T. Tuberosum, 405 00:28:59.440 --> 00:29:08.680 and variety of as I believe ts Tropellium tricholorum variation grandiflorum. 406 00:29:09.279 --> 00:29:12.680 The flexible shoots which first rise from the tubers are 407 00:29:12.720 --> 00:29:16.920 as thin as a fine twine. One such shoot revolved 408 00:29:17.000 --> 00:29:19.960 in a course opposed to the sun at an average rate, 409 00:29:20.400 --> 00:29:24.240 judging from three revolutions, of one hour twenty three minutes, 410 00:29:24.759 --> 00:29:28.400 but no doubt the direction of the revolving movement is variable. 411 00:29:29.279 --> 00:29:32.799 When the plants have grown tall and are branched, all 412 00:29:32.920 --> 00:29:36.880 of the many lateral shoots revolve the stem, whilst young 413 00:29:37.039 --> 00:29:41.000 twines regularly round a thin vertical stick, and in one 414 00:29:41.079 --> 00:29:44.319 case I counted eight spiral turns in the same direction. 415 00:29:45.240 --> 00:29:48.920 But when grown older, the stem often runs straight up 416 00:29:48.960 --> 00:29:52.839 for a space, and, being arrested by the clasping petules, 417 00:29:53.160 --> 00:29:57.480 makes one or two spires in a reverse direction. Until 418 00:29:57.519 --> 00:30:00.160 the plant grows to a

height of two or three feet, 419 00:30:00.480 --> 00:30:03.000 requiring about a month from the time when the first 420 00:30:03.039 --> 00:30:07.440 shoot appears above ground, No true leaves are produced, but 421 00:30:07.599 --> 00:30:11.960 in their place filaments colored like the stem. The extremities 422 00:30:12.000 --> 00:30:15.279 of these filaments are pointed, a little flattened, and furrowed 423 00:30:15.319 --> 00:30:19.519 on the upper surface. They never become developed into leaves. 424 00:30:20.319 --> 00:30:23.680 As the plant grows in height, new filaments are produced 425 00:30:23.920 --> 00:30:28.359 with slightly enlarged tips, then others bearing on each side 426 00:30:28.400 --> 00:30:32.039 of the enlarged medial tip a rudimentary segment of a leaf. 427 00:30:32.559 --> 00:30:36.160 Soon other segments appear, and at last a perfect leaf 428 00:30:36.240 --> 00:30:40.240 is formed with seven deep segments, so that on the 429 00:30:40.279 --> 00:30:43.680 same plant we may see every step from tendril like 430 00:30:43.759 --> 00:30:48.799 clasping filaments to perfect leaves with clasping petioles. After the 431 00:30:48.839 --> 00:30:51.759 plant has grown to a considerable height and is secured 432 00:30:51.799 --> 00:30:54.599 to its support by the petioles of the true leaves, 433 00:30:54.920 --> 00:30:57.599 the clasping filaments on the lower part of the stem 434 00:30:57.680 --> 00:31:00.680 wither and drop off, so that they form only a 435 00:31:00.720 --> 00:31:05.599 temporary surface. These filaments, or rudimentary leaves, as well as 436 00:31:05.640 --> 00:31:09.119 the petigles of the perfect leaves, whilst young, are highly 437 00:31:09.160 --> 00:31:12.880 sensitive on all sides to a touch. The slightest rub 438 00:31:12.960 --> 00:31:16.680 caused them to curve upwards, to curve towards the rubed 439 00:31:16.759 --> 00:31:20.599 side in about three minutes, and one bend itself into 440 00:31:20.640 --> 00:31:26.160 a ring in six minutes. They subsequently become straight when, however, 441 00:31:26.279 --> 00:31:30.680 they have once completely clasped a stick. If this is removed, 442 00:31:30.960 --> 00:31:34.839 they do not straighten themselves. The most remarkable fact, and 443 00:31:34.960 --> 00:31:37.960 one which I have observed in no other species of 444 00:31:38.000 --> 00:31:40.920 this genus. Is that the filaments and the petioles of 445 00:31:40.960 --> 00:31:44.759 the young leaves, if they catch no object, after standing 446 00:31:44.799 --> 00:31:48.680 for some days in their original positions, spontaneously and slowly 447 00:31:48.799 --> 00:31:52.720 oscillate a little from side to side, then move towards 448 00:31:52.720 --> 00:31:56.839 the stem and clasp in. They likewise often become, after 449 00:31:57.000 --> 00:32:01.920 time in some degree spirally contracted. They therefore fully deserve 450 00:32:02.000 --> 00:32:05.319 to be called tendrils, as they are used for climbing, 451

00:32:05.480 --> 00:32:10.279 are sensitive to a touch, move spontaneously, and ultimately contract 452 00:32:10.400 --> 00:32:14.680 into a spire, though an imperfect one. The present species 453 00:32:14.720 --> 00:32:18.160 would have been clasped amongst the tendril bearers had not 454 00:32:18.279 --> 00:32:23.200 these characters been confined to early youth. During maturity, it 455 00:32:23.319 --> 00:32:29.119 is a true leaf climber. Tropallium as urum, an upper 456 00:32:29.160 --> 00:32:33.079 internode made for revolutions following the sun at an average 457 00:32:33.160 --> 00:32:36.720 rate of one hour forty seven minutes. The stem twined 458 00:32:36.799 --> 00:32:40.039 spirally round to support in the same irregular manner as 459 00:32:40.119 --> 00:32:44.640 that of the last species. Rudimentary leaves or filaments do 460 00:32:44.720 --> 00:32:48.799 not exist. The peticles of the young leaves are very sensitive. 461 00:32:49.319 --> 00:32:51.759 A slight rub with a twig caused one to move 462 00:32:51.799 --> 00:32:56.200 perceptively in five minutes, and another in six minutes, the 463 00:32:56.240 --> 00:32:59.599 former being bent at right angles in fifteen minutes and 464 00:32:59.680 --> 00:33:03.200 became straight again in between five hours and six hours. 465 00:33:03.920 --> 00:33:06.119 A loop of thread wing one eighth of the grain 466 00:33:06.240 --> 00:33:13.480 caused another petiole to curve Tropolium Tropealium pentaphyllum. This species 467 00:33:13.519 --> 00:33:16.960 has not the power of spirally twining, which seems due 468 00:33:17.359 --> 00:33:20.559 not so much to want of flexibility in the stem 469 00:33:20.759 --> 00:33:24.880 as to continual interference from the clasping petioles. An upper 470 00:33:25.000 --> 00:33:28.720 internode made three revolutions following the sun, at an average 471 00:33:28.799 --> 00:33:32.200 rate of one hour forty six minutes. The main purpose 472 00:33:32.279 --> 00:33:35.519 of the revolving movement in all the species of Tropellium 473 00:33:36.000 --> 00:33:39.000 manifestly is to bring the petioles into contact with some 474 00:33:39.160 --> 00:33:43.119 supporting object. The petule of a young thief after a 475 00:33:43.160 --> 00:33:46.880 slight lub became curved in six minutes, another on a 476 00:33:46.920 --> 00:33:50.519 cold day in twenty minutes, and others in from eight 477 00:33:50.559 --> 00:33:54.920 minutes to ten minutes. Their coverature usually increased greatly in 478 00:33:55.000 --> 00:33:58.720 from fifteen minutes to twenty minutes, and they become straight 479 00:33:58.799 --> 00:34:02.240 again in between five hours and six hours, But on one 480 00:34:02.119 --> 00:34:06.279 occasion in three hours when a petiole has fairly clasped 481 00:34:06.359 --> 00:34:09.159 a stick. It is not able on removal of the 482 00:34:09.159 --> 00:34:12.840 stick to straightness, the free upper part of one, the 483 00:34:12.880 --> 00:34:16.360 base of which

had already clasped a stick, still retained 484 00:34:16.360 --> 00:34:19.519 the power of movement a loop of thread when one 485 00:34:19.599 --> 00:34:22.280 eighth of a grain caused a petiole to curve, but 486 00:34:22.440 --> 00:34:26.639 the stimulus was not sufficient, the loop remaining suspended to 487 00:34:26.719 --> 00:34:30.480 cause a permanent flexion. If a much heavier loop be 488 00:34:30.559 --> 00:34:33.039 placed in the angle between the petiole and the stem, 489 00:34:33.320 --> 00:34:37.000 it produces no effect, whereas we have seen with Comatis 490 00:34:37.000 --> 00:34:40.559 montana that the ankle between the stem and the petroole 491 00:34:40.679 --> 00:34:46.480 is sensitive Tropelium peragrinum. The first formed internodes of a 492 00:34:46.519 --> 00:34:50.119 young plant did not revolve, resembling in this respect those 493 00:34:50.159 --> 00:34:53.320 of a twining plant. In an older plant, the four 494 00:34:53.400 --> 00:34:57.840 upper internodes made three irregular revolutions in a course opposed 495 00:34:57.840 --> 00:35:00.079 to the sun, at an average rate of one one 496 00:35:00.159 --> 00:35:03.360 hour forty eight minutes. It is remarkable that the average 497 00:35:03.440 --> 00:35:08.159 rate of revolution taken, however, but from few observations, is 498 00:35:08.280 --> 00:35:12.000 very nearly the same in this and the two last species, 499 00:35:12.360 --> 00:35:15.559 namely one hour forty seven minutes, one hour forty six 500 00:35:15.599 --> 00:35:19.320 minutes and one hour forty eight minutes. The present species 501 00:35:19.360 --> 00:35:23.480 cannot twine spirally, which seems mainly due to the rigidity 502 00:35:23.559 --> 00:35:26.840 of the steam. In a very young plant which did 503 00:35:26.880 --> 00:35:31.039 not revolve, the petioles were not sensitive. In older plants. 504 00:35:31.039 --> 00:35:34.159 The petioles of quite young leaves and of leaves as 505 00:35:34.239 --> 00:35:37.920 much as an inch and a quarter in diameter are sensitive. 506 00:35:38.639 --> 00:35:41.440 A moderate rub caused one to curve in ten minutes 507 00:35:41.519 --> 00:35:45.360 and the others in twenty minutes. They became straight again 508 00:35:45.440 --> 00:35:48.400 in between five hours, forty five minutes and eight hours. 509 00:35:49.239 --> 00:35:52.960 Petioles which have naturally come into contact with a stick 510 00:35:53.119 --> 00:35:57.119 sometimes take two turns round it. After they have clasped 511 00:35:57.119 --> 00:36:00.960 a support, they become rigid and hard. Are less sensitive 512 00:36:01.039 --> 00:36:04.639 to await than in previous species. For loops of string 513 00:36:04.800 --> 00:36:08.119 weighing zero point eight to two of a gram fifty 514 00:36:08.159 --> 00:36:13.239 three point fourteen milligrams did not cause any carpeture, but 515 00:36:13.320 --> 00:36:16.320 a loop of double this weight one point sixty four 516 00:36:16.400 --> 00:36:21.840 grains acted. Tropolium elegance I did not make any many 517 00:36:21.920 --> 00:36:27.119 observations on this species. The short and stiff internodes revolve irregularly, 518 00:36:27.440 --> 00:36:32.480 describing small oval figures. One oval was completed in three hours. 519 00:36:33.079 --> 00:36:36.679 A young petrole, when rubbed, became slightly curved in seventeen minutes, 520 00:36:36.880 --> 00:36:40.239 and afterwards much more so. It was nearly straight again 521 00:36:40.320 --> 00:36:46.000 in eight hours. Tropelium tuberosum on a plant nine inches 522 00:36:46.039 --> 00:36:49.320 in height, the internodes did not move at all, but 523 00:36:49.480 --> 00:36:52.800 on an older plant they moved irregularly and made small, 524 00:36:52.920 --> 00:36:57.519 imperfect ovals. These movements could be detected only by being 525 00:36:57.559 --> 00:37:01.599 traced on a bell glass placed over the place. Sometimes 526 00:37:01.639 --> 00:37:05.960 the shoots stood still for hours. During some days they 527 00:37:06.000 --> 00:37:09.440 moved only in one direction, in a crooked line. On 528 00:37:09.559 --> 00:37:13.960 other days they made small, irregular spires or circles, one 529 00:37:14.039 --> 00:37:18.039 being completed in about four hours. The extreme points reached 530 00:37:18.039 --> 00:37:20.800 by the apex of the shoot were only about one 531 00:37:21.039 --> 00:37:24.280 or one and a half inches asunder. Yet, this slight 532 00:37:24.400 --> 00:37:28.880 movement brought the petioles into contact with some closely surrounding twigs, 533 00:37:29.280 --> 00:37:33.880 which were then clasped. With the listening power of spontaneously 534 00:37:34.199 --> 00:37:39.119 revolving compared with that of the previous species, the sensitiveness 535 00:37:39.119 --> 00:37:42.840 of the petioles is also diminished. These, when rubbed a 536 00:37:42.880 --> 00:37:47.039 few times, did not become curved until half an hour 537 00:37:47.119 --> 00:37:51.360 had elapsed. The curvature increased during the next two hours, 538 00:37:51.639 --> 00:37:55.519 and then very slowly decreased, so that they sometimes required 539 00:37:55.519 --> 00:37:59.760 twenty four hours to become straight again. Extremely young leaves 540 00:37:59.800 --> 00:38:04.039 have active petioles, one with the lamina only zero point 541 00:38:04.079 --> 00:38:07.360 one point five of an inch in diameter, that is 542 00:38:07.519 --> 00:38:11.360 about a twentieth of the full size firmly clasping a 543 00:38:11.440 --> 00:38:14.400 thin twig. But these grown to a quarter of their 544 00:38:14.480 --> 00:38:21.039 full size can likewise act Tropallium minus question mark. The 545 00:38:21.079 --> 00:38:26.440 internodes of a variety named dwarf crimson Nostritium did not revolve, 546 00:38:26.800 --> 00:38:29.719 but moved in a rather irregular course during the day 547 00:38:29.800 --> 00:38:33.280 to the light and from the light at night. The petioles, 548 00:38:33.320 -->

00:38:37.199 when well rubbed, showed no power of curving, nor could 549 00:38:37.239 --> 00:38:40.960 I see that they ever clasped any neighboring object. We 550 00:38:41.039 --> 00:38:44.480 have seen in this genus a gradiation from species such 551 00:38:44.519 --> 00:38:49.840 as T. Tricholorum, which have extremely sensitive petioles and internodes 552 00:38:49.880 --> 00:38:54.440 which rapidly revolve and spirally twine up a support to 553 00:38:54.519 --> 00:38:58.760 other species such as T. Elegance and TA. Turberosum, that 554 00:38:58.840 --> 00:39:01.599 the petioles of which are much less sensitive, and the 555 00:39:01.639 --> 00:39:06.159 internodes of which have very feeble revolving powers and cannot 556 00:39:06.199 --> 00:39:10.400 spirally twine around a support to this last species, which 557 00:39:10.440 --> 00:39:14.840 has entirely lost or never acquired these faculties. From the 558 00:39:14.880 --> 00:39:17.639 general character of the genus, the loss of power, it 559 00:39:17.639 --> 00:39:22.239 seems the more probable alternative in the present species. In 560 00:39:22.360 --> 00:39:26.599 Tielegans and probably in others, the flower peduncle, as soon 561 00:39:26.599 --> 00:39:31.000 as the seed capsule begins to swell spontaneously, bends abruptly 562 00:39:31.079 --> 00:39:35.519 downwards and becomes somewhat convoluted. If a stick stands in 563 00:39:35.559 --> 00:39:39.360 the way, it is to a certain extent clasped, But 564 00:39:39.639 --> 00:39:41.800 as far as I have been able to observe, this 565 00:39:41.920 --> 00:39:47.760 clasping movement is independent of the stimulus from contact enter 566 00:39:47.840 --> 00:39:54.679 Hinnae in this tribe Limbley of the Scrophillarisa. At least 567 00:39:54.800 --> 00:40:01.360 four of the seven included genera have leaf climbing species. Barcleyana, 568 00:40:02.280 --> 00:40:06.679 a thin, slightly bowed chute, made two revolutions following the sun, 569 00:40:06.880 --> 00:40:10.440 each in three hours seventeen minutes. On the previous day, 570 00:40:10.519 --> 00:40:14.559 the same shoote revolved in an opposite direction. The shoots 571 00:40:14.599 --> 00:40:18.039 do not twine spirally, but climb excellently by the aid 572 00:40:18.119 --> 00:40:23.119 of their young and sensitive petioles. These petioles, when lightly rubbed, 573 00:40:23.480 --> 00:40:27.360 move after a considerable interval of time, and subsequently becomes 574 00:40:27.400 --> 00:40:30.599 straight again. A loop of thread wing one eighth of 575 00:40:30.639 --> 00:40:35.719 the grain caused them to bend Morandia semper florins. This 576 00:40:35.920 --> 00:40:39.440 freely growing species climbs exactly like the last by the 577 00:40:39.480 --> 00:40:43.280 aid of its sensitive petioles. A young internode made two 578 00:40:43.320 --> 00:40:46.639 circles each in one hour forty six minutes, so that 579 00:40:46.719 --> 00:40:50.159 it moved almost twice as rapidly as the last species. 580 00:40:50.800 --> 00:40:53.639 The internodes are not in the least sensitive to a 581 00:40:53.719 --> 00:40:57.360 touch or pressure. I mention this because they are sensitive 582 00:40:57.440 --> 00:41:03.159 in a closely allied genus, namely Lophospermum. The present species 583 00:41:03.239 --> 00:41:07.639 is unique in one respect. Mole asserts page forty five 584 00:41:08.039 --> 00:41:11.880 that the flower peduncles, as well as the petioles wind 585 00:41:12.159 --> 00:41:16.360 like tendrils, but he classes as tendrils such objects as 586 00:41:16.400 --> 00:41:21.119 the spiral flower stalks of the Vallisinaria. This remark and 587 00:41:21.199 --> 00:41:25.320 the fact of the flower peduncles being decidedly flectuous, led 588 00:41:25.360 --> 00:41:29.760 me carefully to examine them. They never act as true tendrils. 589 00:41:30.199 --> 00:41:33.320 I repeatedly placed thin sticks in contact with young and 590 00:41:33.400 --> 00:41:36.880 old peduncles, and I allowed nine vigorous plants to grow 591 00:41:36.920 --> 00:41:40.119 through an entangled mass of branches, but in no one 592 00:41:40.320 --> 00:41:44.679 instance do they bend round any object. It is indeed, 593 00:41:44.800 --> 00:41:47.880 in the highest degree improbable that this should occur, for 594 00:41:47.960 --> 00:41:52.039 they are generally developed on branches which have already securely 595 00:41:52.079 --> 00:41:55.719 clashed a support by the petioles of their leaves, and 596 00:41:55.880 --> 00:41:59.519 when borne on a free depending branch, they are not 597 00:41:59.559 --> 00:42:03.320 produced by the terminal portion of the internode, which alone 598 00:42:03.360 --> 00:42:06.440 has the power of revolving, so that they could be 599 00:42:06.559 --> 00:42:12.159 brought only by accident into contact with any neighboring object. Nevertheless, 600 00:42:12.239 --> 00:42:16.559 and this is the remarkable fact, the flower peduncles, whilst young, 601 00:42:17.000 --> 00:42:21.519 exhibit feeble revolving powers, and are slightly sensitive to a touch. 602 00:42:22.239 --> 00:42:25.599 Having selected some stems which had firmly clasped a stick 603 00:42:25.679 --> 00:42:29.320 by their petioles, and having placed a bell glass over them, 604 00:42:29.679 --> 00:42:33.320 I traced the movements of the young flower peduncles. The 605 00:42:33.400 --> 00:42:37.920 tracing generally formed a short and extremely irregular line with 606 00:42:38.039 --> 00:42:41.639 little loops in its course. A young peduncle one one 607 00:42:41.719 --> 00:42:45.000 half inch in length was carefully observed during a whole day, 608 00:42:45.400 --> 00:42:49.039 and it made four and a half narrow, vertical, irregular 609 00:42:49.079 --> 00:42:52.480 and short ellipses each at an average rate of about 610 00:42:52.559 --> 00:42:57.199 two hours. Twenty five minutes. An adjoining peduncle described during 611 00:42:57.199 --> 00:43:01.719 the same time similar though fewer

ellipses, as the plant 612 00:43:01.760 --> 00:43:05.519 had occupied for some time exactly the same position. These 613 00:43:05.559 --> 00:43:08.159 movements could not be attributed to any change in the 614 00:43:08.159 --> 00:43:12.000 action of the light Peduncles old enough for the colored 615 00:43:12.039 --> 00:43:16.079 petals to be just visible. Do not move with respect 616 00:43:16.199 --> 00:43:20.199 to irritability. I rubbed two young peduncles, one one half 617 00:43:20.280 --> 00:43:24.039 inchine length a few times, very lightly with a thin twig. 618 00:43:24.719 --> 00:43:26.800 One was rubbed on the upper and the other on 619 00:43:26.840 --> 00:43:30.360 the lower side, and they became, in between four hours 620 00:43:30.400 --> 00:43:35.159 and five hours distinctly bowed towards these sides. In twenty 621 00:43:35.199 --> 00:43:39.239 four hours, subsequently they straightened themselves. Next day they were 622 00:43:39.320 --> 00:43:42.719 rubbed on the opposite sides, and they became perceptibly curved 623 00:43:42.760 --> 00:43:47.519 towards these sides. Two other and younger peduncles three fourths 624 00:43:47.519 --> 00:43:51.199 of an inchine length, were lightly rubbed on their adjoining sides, 625 00:43:51.440 --> 00:43:54.480 and they became so much curved towards one another that 626 00:43:54.559 --> 00:43:57.920 the arcs of the bows stood at nearly right angles 627 00:43:57.960 --> 00:44:01.639 to their previous direction. This was the greatest movement seen 628 00:44:01.719 --> 00:44:06.880 by me. Subsequently, they straightened themselves. Other peduncles so young 629 00:44:06.920 --> 00:44:09.320 as to be only three tenths of an inchine length 630 00:44:09.400 --> 00:44:13.639 became curved when rubbed. On the other hand, peduncles above 631 00:44:13.679 --> 00:44:16.679 one one half inchin length required to be rubbed two 632 00:44:16.800 --> 00:44:20.480 or three times, and then became only just perceptibly bowed. 633 00:44:21.360 --> 00:44:25.000 Loops of thread suspended on the peduncles produced no effect. 634 00:44:25.519 --> 00:44:29.159 Loops of string, however, weighing zero point eight two and 635 00:44:29.440 --> 00:44:32.880 one point sixty four of a grain sometimes caused a 636 00:44:32.920 --> 00:44:37.000 slight curvature, but they were never closely clasped, as were 637 00:44:37.079 --> 00:44:40.880 the far lighter groops of thread by the petioles. In 638 00:44:41.079 --> 00:44:44.000 the nine vigorous plants observed by me, it is certain 639 00:44:44.079 --> 00:44:48.519 that neither the slight spontaneous movements nor the slight sensitiveness 640 00:44:48.519 --> 00:44:52.280 of the flower peduncles aided the plants in climbing. If 641 00:44:52.320 --> 00:44:57.320 any member of the scrofulari Ica had possessed tendrils produced 642 00:44:57.360 --> 00:45:00.719 by the modification of flower peduncles, I should have thought 643 00:45:00.760 --> 00:45:04.480 that this species of Morandia had

perhaps retained a useless 644 00:45:04.599 --> 00:45:08.199 or rudimentary vestige of a former habit. But this view 645 00:45:08.239 --> 00:45:11.760 cannot be maintained. We may suspect that, owing to the 646 00:45:11.800 --> 00:45:16.079 principle of correlation, the power of movement has been transferred 647 00:45:16.159 --> 00:45:20.159 to the flower peduncles from the young internodes, and sensitiveness 648 00:45:20.239 --> 00:45:23.920 from the young petioles. But to whatever cause these capacities 649 00:45:23.960 --> 00:45:27.719 are due, the case is interesting, for by a little 650 00:45:27.840 --> 00:45:31.480 increase in power through natural selection, they might easily have 651 00:45:31.559 --> 00:45:34.840 been rendered as useful to the plant and criming as 652 00:45:34.880 --> 00:45:38.400 are the flower peduncles, hereafter to be described of the 653 00:45:38.519 --> 00:45:46.559 vitus or cardiospermam rhydochitan volubile. A long flexible shoot swept 654 00:45:46.599 --> 00:45:50.280 a large circle following the sun in five hours thirty minutes, 655 00:45:50.719 --> 00:45:53.360 and as the day became warmer, a second circle was 656 00:45:53.400 --> 00:45:57.480 completed in four hours ten minutes. The shoots sometimes made 657 00:45:57.519 --> 00:46:00.800 a whole or half spy around a vertical step. They 658 00:46:00.880 --> 00:46:04.559 then run straight up for a space, and afterwards transpirally 659 00:46:04.639 --> 00:46:08.760 in an opposite direction. The petioles of very young leaves, 660 00:46:08.800 --> 00:46:11.920 about one tenth of their full size, are highly sensitive 661 00:46:12.280 --> 00:46:15.239 and bend towards a side which is touched, but they 662 00:46:15.280 --> 00:46:19.400 do not move quickly. One was perceptibly curved in one 663 00:46:19.440 --> 00:46:23.000 hour ten minutes after being lightly rubbed, and became considerably 664 00:46:23.039 --> 00:46:27.440 curved in five hours forty minutes. Some others were scarcely curved. 665 00:46:27.480 --> 00:46:30.840 In five hours thirty minutes, but distinctly so in six 666 00:46:30.920 --> 00:46:35.159 hours thirty minutes. A curvature was perceptible in one petiole 667 00:46:35.239 --> 00:46:38.800 in between four hours thirty minutes and five hours after 668 00:46:38.840 --> 00:46:42.280 the suspension of a little loop of string. A loop 669 00:46:42.320 --> 00:46:45.320 of fine cotton thread weighing one sixteenth of a grain 670 00:46:45.840 --> 00:46:49.519 four point zero five milligrams not only caused a petiole 671 00:46:49.599 --> 00:46:53.519 slowly to bend, but was ultimately so firmly clasped that 672 00:46:53.559 --> 00:46:57.679 it could be withdrawn only by some little force. The petioles, 673 00:46:57.760 --> 00:47:00.920 when coming into contact with a stick, take either a 674 00:47:00.960 --> 00:47:04.880 complete or half a turn round it, and ultimately increase 675 00:47:04.960 --> 00:47:08.239 much in thickness. They do not possess the power of 676 00:47:08.280 --> 00:47:17.079 spontaneously revolving Lofospermum scandons variation purpureum. Some long, moderately thin 677 00:47:17.199 --> 00:47:20.559 internodes made for revolutions at an average rate of three 678 00:47:20.559 --> 00:47:25.119 hours fifteen minutes. The course pursued with very irregular namely 679 00:47:25.159 --> 00:47:29.280 an extremely narrow ellipse, a large circle, an irregular spire, 680 00:47:29.639 --> 00:47:33.280 or a zigzag line, and sometimes the apex stood still. 681 00:47:34.159 --> 00:47:37.280 The young petioles, when brought by the revolving movement into 682 00:47:37.280 --> 00:47:41.960 contact with sticks, clasped them, and soon increased considerably in thickness. 683 00:47:42.480 --> 00:47:44.960 But they were not quite so sensitive to await as 684 00:47:44.960 --> 00:47:48.159 those of the rhodoor kitten, for loops of thread weighing 685 00:47:48.280 --> 00:47:50.719 one eighth of a grain did not always cause them 686 00:47:50.719 --> 00:47:54.519 to bend. This plant presents a case not observed by 687 00:47:54.559 --> 00:47:58.199 me in any other leaf climber or twiner, namely, that 688 00:47:58.280 --> 00:48:01.199 the young internodes of the stem are sensitive to a touch. 689 00:48:01.800 --> 00:48:05.239 When a petiole of this species clasps a stick, it 690 00:48:05.320 --> 00:48:08.320 draws the base of the internode against it, and then 691 00:48:08.360 --> 00:48:11.760 the internode itself bends towards the stick, which is caught 692 00:48:11.800 --> 00:48:14.159 between the stem and the petiole, as by a pair 693 00:48:14.199 --> 00:48:18.760 of painters. The internode afterwards straightens itself, excepting the part 694 00:48:18.880 --> 00:48:23.719 in actual contact with the stick. Young internodes alone are sensitive, 695 00:48:24.159 --> 00:48:28.000 and these are sensitive on all sides along their whole length. 696 00:48:28.719 --> 00:48:32.239 I made fifteen trials by twice or thrice lightly rubbing 697 00:48:32.400 --> 00:48:36.760 with a thin twig several internodes, and in about two hours, 698 00:48:36.920 --> 00:48:39.440 but in one case, in three hours all were bent. 699 00:48:40.280 --> 00:48:44.320 They became straight again in about four hours afterwards. An 700 00:48:44.360 --> 00:48:47.360 internode which was rubbed as often as six or seven 701 00:48:47.440 --> 00:48:51.599 times became just perceptibly curved in one hour fifteen minutes, 702 00:48:51.800 --> 00:48:55.480 and in three hours the curvature increased much it became 703 00:48:55.559 --> 00:48:58.840 straight again. In the course of the succeeding night, I 704 00:48:58.960 --> 00:49:01.960 rubbed some internotes one day on one side, and the 705 00:49:02.000 --> 00:49:04.599 next day either on the opposite side or at right 706 00:49:04.639 --> 00:49:07.800 angles to the first side, and the curvature was always 707 00:49:07.840 --> 00:49:12.119 towards the rubbed side. According to Palm page sixty

three, 708 00:49:12.440 --> 00:49:17.000 the petioles of Linaria chirosa, and to a limited degree, 709 00:49:17.039 --> 00:49:21.800 those of L. Lantine, have the power of clasping a support. 710 00:49:22.159 --> 00:49:27.840 Solnica solanum jasminoidas. Some of the species in this large 711 00:49:27.880 --> 00:49:30.960 genus are twiners, but the present species is a true 712 00:49:31.039 --> 00:49:35.320 leaf climber. A long, nearly upright chute made four revolutions, 713 00:49:35.400 --> 00:49:39.079 moving against the sun very regularly, at an average rate 714 00:49:39.119 --> 00:49:42.719 of three hours twenty six minutes. The shoots, however, sometimes 715 00:49:42.760 --> 00:49:47.119 stood still. It is considered a greenhouse plant, but when 716 00:49:47.199 --> 00:49:50.559 kept there, the petioles took several days to clasp a stick. 717 00:49:51.199 --> 00:49:54.079 In the hothouse, a stick was clasped in seven hours. 718 00:49:54.639 --> 00:49:57.239 In the greenhouse. A petiole was not affected by a 719 00:49:57.239 --> 00:50:01.119 loop of string suspended during several days and weighing two 720 00:50:01.159 --> 00:50:05.360 and one grains one hundred and sixty three milligrams. But 721 00:50:05.440 --> 00:50:07.519 in the hot house one was made to curve by 722 00:50:07.559 --> 00:50:10.760 a loop weighing one point sixty four grains one hundred 723 00:50:10.800 --> 00:50:14.360 and six point twenty seven milligrams, and on the removal 724 00:50:14.400 --> 00:50:18.280 of the stream it became straight again. Another petiole was 725 00:50:18.320 --> 00:50:21.119 not at all acted on by a loop weighing only 726 00:50:21.239 --> 00:50:24.280 zero point eight two of a grain fifty three point 727 00:50:24.360 --> 00:50:28.239 fourteen milligrams. We have seen that the petioles of some 728 00:50:28.360 --> 00:50:31.559 other leaf climbers are affected by one thirteenth of this 729 00:50:31.679 --> 00:50:34.960 latter weight. In this species and in no other leaf 730 00:50:35.000 --> 00:50:38.199 climber seen by me, a full grown leaf is capable 731 00:50:38.239 --> 00:50:41.440 of clasping a stick, but in the greenhouse the movement 732 00:50:41.599 --> 00:50:45.519 was so extraordinarily slow that the act required several weeks. 733 00:50:46.000 --> 00:50:48.440 On each succeeding week it was clear that the petiole 734 00:50:48.519 --> 00:50:51.719 had become more and more curved, until at last it 735 00:50:51.800 --> 00:50:56.320 firmly clasped the stick. A flexible petiole of a half 736 00:50:56.440 --> 00:50:59.519 or a quart grown leaf which has clasped an object 737 00:50:59.519 --> 00:51:03.760 four three or four days, increases much in thickness, and 738 00:51:03.920 --> 00:51:07.280 after several weeks becomes so wonderfully hard and rigid that 739 00:51:07.360 --> 00:51:11.119 it can hardly be removed from its support. When comparing 740 00:51:11.159 --> 00:51:14.239 a thin transverse slice of such a petiole with one 741 00:51:14.280 --> 00:51:17.320 from an older leaf growing close beneath, which had not 742 00:51:17.400 --> 00:51:21.360 clasped anything, its diameter was found to be fully doubled 743 00:51:21.639 --> 00:51:25.719 and its structure greatly changed. In two other petioles similarly 744 00:51:25.760 --> 00:51:29.199 compared and here represented, the increase in diameter was not 745 00:51:29.320 --> 00:51:32.280 quite so great. In the section of the petiole in 746 00:51:32.320 --> 00:51:36.320 its ordinary state a we see a semi lunar band 747 00:51:36.400 --> 00:51:40.239 of circular tissue not well shown in the woodcut, differing 748 00:51:40.280 --> 00:51:43.840 slightly an appearance from that outside it, and including three 749 00:51:44.000 --> 00:51:48.480 closely approximate groups of dark vessels near the upper surface 750 00:51:48.519 --> 00:51:52.119 of the petiole beneath two exterior ridges. There are two 751 00:51:52.280 --> 00:51:56.119 other small circular groups of vessels in the section of 752 00:51:56.159 --> 00:52:00.480 the petiole b which had clasped. During several weeks stick 753 00:52:00.880 --> 00:52:04.599 the two exterior ridges have become much less prominent, and 754 00:52:04.679 --> 00:52:08.079 the two groups of woody vessels beneath them much increased 755 00:52:08.079 --> 00:52:12.079 in diameter. The semi lunar band has been converted into 756 00:52:12.119 --> 00:52:16.360 a complete ring of very hard white woody tissue, with 757 00:52:16.480 --> 00:52:21.199 lines radiating from the center the three groups of vessels, which, 758 00:52:21.360 --> 00:52:26.039 though near together, were before distinct, are now completely blended. 759 00:52:26.679 --> 00:52:29.760 The upper part of this ring of woody vessels, formed 760 00:52:29.800 --> 00:52:32.599 by the prolongation of the horns of the original semi 761 00:52:32.679 --> 00:52:36.559 lunar band, is narrower than the lower part and slightly 762 00:52:36.639 --> 00:52:40.920 less compact. This petiole, after clasping the stick, had actually 763 00:52:40.960 --> 00:52:44.000 become thicker than the stem from which it arose, and 764 00:52:44.079 --> 00:52:47.000 this was chiefly due to the increased thickness of the 765 00:52:47.079 --> 00:52:51.199 ring of wood. This ring presented, both in a transverse 766 00:52:51.239 --> 00:52:55.199 and longitudinal section, a closely similar structure to that of 767 00:52:55.199 --> 00:52:59.280 the stem. It is a singular morphological fact that the 768 00:52:59.280 --> 00:53:03.159 petiole should thus acquire a structure almost identically the same 769 00:53:03.440 --> 00:53:06.199 with that of the axis. It is a still more 770 00:53:06.239 --> 00:53:09.840 singular physiological fact that so great a chain should have 771 00:53:09.880 --> 00:53:12.920 been induced by the mere act of clasping a support 772 00:53:14.199 --> 00:53:20.360 fumeriaca Fumeria ophicianalis. It could not have been anticipated that 773 00:53:20.480 -->

00:53:23.239 so lowly a plant as this fumaria could have been 774 00:53:23.320 --> 00:53:26.320 a climber. It climbs by the aid of the main 775 00:53:26.440 --> 00:53:29.800 and lateral petioles of its compound leaves, and even the 776 00:53:29.880 --> 00:53:33.800 much flattened terminal portion of the petiole can seize a support. 777 00:53:34.599 --> 00:53:37.280 I have seen a substance as soft as a withered 778 00:53:37.280 --> 00:53:41.800 blade of grass. Cot Petioles which have clasped an object 779 00:53:41.960 --> 00:53:46.800 ultimately become rather thicker and more cylindrical. On lightly rubbing 780 00:53:46.840 --> 00:53:50.440 several petioles with a twig, they became perceptibly curved in 781 00:53:50.519 --> 00:53:55.599 one hour fifteen minutes and subsequently strengthened themselves. A stick 782 00:53:55.719 --> 00:53:59.599 gently placed in the angle between two subpetoles excited them 783 00:53:59.760 --> 00:54:03.880 to move and was almost clasped in nine hours. A 784 00:54:03.880 --> 00:54:06.639 loop of thread weighing one eighth of the grain caused 785 00:54:06.719 --> 00:54:10.559 after twelve hours and before twenty hours, had elapsed a 786 00:54:10.639 --> 00:54:14.960 considerable curvature, but it was never fairly clasped by petiole. 787 00:54:15.800 --> 00:54:20.000 The young internodes are in continual movement, which is considerable 788 00:54:20.039 --> 00:54:23.679 in extent but very irregular. A zigzag line or a 789 00:54:23.719 --> 00:54:27.440 spire crossing itself, or a figure of eight being formed 790 00:54:28.239 --> 00:54:31.480 the courus during twelve hours, when traced on a bell glass, 791 00:54:31.639 --> 00:54:38.440 apparently represented about four ellipses. The leaves themselves likewise move spontaneously, 792 00:54:38.800 --> 00:54:42.079 the main petiles curving themselves in accordance with the movements 793 00:54:42.159 --> 00:54:44.760 of the internodes, so that when the latter moved to 794 00:54:44.800 --> 00:54:48.639 one side, the petioles moved to the same side, then, 795 00:54:48.800 --> 00:54:53.760 becoming straight, reversed their curvature. The petioles, however, do not 796 00:54:53.960 --> 00:54:56.880 move over a wide space, as could be seen when 797 00:54:56.920 --> 00:55:00.320 a shoot was securely tied to a stick. A leaf 798 00:55:00.440 --> 00:55:03.760 in this case followed an irregular course like that made 799 00:55:03.800 --> 00:55:09.800 by the internotes. Adlumia siherosa I raised some plants late 800 00:55:09.880 --> 00:55:12.880 in the summer. They formed very fine leaves, but threw 801 00:55:13.000 --> 00:55:18.400 up no central stem. The first formed leaves were not sensitive. 802 00:55:18.880 --> 00:55:22.039 Some of the later ones were so, but only towards 803 00:55:22.079 --> 00:55:26.559 their extremities, which were thus enabled to clasp sticks. This 804 00:55:26.679 --> 00:55:28.800 could be of no surface to the plant, as these 805 00:55:28.880 --> 00:55:31.840 leaves rose from the ground, but it showed that the 806 00:55:31.880 --> 00:55:34.719 future character of the plant would have been had it 807 00:55:34.719 --> 00:55:38.079 grown tall enough to climb the tip of one of 808 00:55:38.119 --> 00:55:41.599 these basal leaves. Whilst Young described in one hour thirty 809 00:55:41.599 --> 00:55:44.960 six minutes a narrow ellipse open at one end and 810 00:55:45.119 --> 00:55:49.239 exactly three inches in length. A second ellipse, which was broader, 811 00:55:49.360 --> 00:55:52.360 more regular, and shorter viz. Only Two and a half 812 00:55:52.559 --> 00:55:56.559 inches in length, and was completed in two hours two minutes. 813 00:55:57.159 --> 00:56:00.360 From the analogy of humaria and cordillas. I have no 814 00:56:00.440 --> 00:56:04.000 doubt that the interloads of Algumia have the power of revolving. 815 00:56:05.239 --> 00:56:10.280 Corridalis claviculata. This plant is interesting from being in a 816 00:56:10.320 --> 00:56:13.519 condition so exactly intermediate between a leaf climber and a 817 00:56:13.559 --> 00:56:17.039 tendril bearer that it might have been described under either head. 818 00:56:17.480 --> 00:56:20.880 But for reasons hereafter assigned, it has been classed amongst 819 00:56:21.000 --> 00:56:27.320 tendril bearers. Besides the plants being already described, Bignonia unguis 820 00:56:27.400 --> 00:56:31.719 and its close allies, though aided by tendrils, have clasping petioles. 821 00:56:32.159 --> 00:56:36.679 According to Mole page forty, Populos japonicus, one of the 822 00:56:36.719 --> 00:56:42.719 menace promasiae, and a fern the Ophioglossum japonica page thirty nine, 823 00:56:43.119 --> 00:56:46.880 climb by their leaf stalks. We now come to a 824 00:56:46.920 --> 00:56:49.960 small section of plants which climb by means of the 825 00:56:50.199 --> 00:56:54.239 produced mid ribs or tips of their leaves. The lacier 826 00:56:54.800 --> 00:57:00.440 Gloriosa planti. The stem of a half grown plant continually moved, 827 00:57:00.719 --> 00:57:05.119 describing an irregular spire, but sometimes oval figures, with the 828 00:57:05.159 --> 00:57:09.440 longer axis directed in different eyes. It either followed the 829 00:57:09.480 --> 00:57:12.800 sun or moved in an opposite course. And sometimes stood 830 00:57:12.840 --> 00:57:17.119 still before reversing its direction. One oval was completed in 831 00:57:17.159 --> 00:57:21.440 three hours forty minutes. Of two horseshoe shaped figures, one 832 00:57:21.559 --> 00:57:24.199 was completed in four hours thirty five minutes and the 833 00:57:24.239 --> 00:57:28.000 other in three hours. The shoots, in their movements, reached 834 00:57:28.039 --> 00:57:32.239 points between four and five inches asunder. The young leaves 835 00:57:32.239 --> 00:57:35.679 when first developed to stand up nearly vertically, but by 836 00:57:35.679 --> 00:57:38.480 the growth of the axis and by the spontaneous bending 837

00:57:38.519 --> 00:57:41.199 down of the terminal half of the leaf, they soon 838 00:57:41.280 --> 00:57:45.880 become much inclined and ultimately horizontal. The end of the 839 00:57:45.960 --> 00:57:49.920 leaf forms a narrow ribbon like thickened projection, which at 840 00:57:50.000 --> 00:57:53.440 first is nearly straight, but by the time the leaf 841 00:57:53.559 --> 00:57:57.960 gets into an inclined position, the end bends downwards into 842 00:57:57.960 --> 00:58:01.599 a well formed hook. This hook is now strong and 843 00:58:01.719 --> 00:58:05.440 rigid enough to catch any object, and, when caught, to 844 00:58:05.480 --> 00:58:09.239 anchor the plant and stop the revolving movement. Its inner 845 00:58:09.280 --> 00:58:12.480 surface is sensitive, but not in nearly so high a 846 00:58:12.559 --> 00:58:16.360 degree as that of the many before described petioles. For 847 00:58:16.440 --> 00:58:19.360 a loop of string weighing one point sixty four grain 848 00:58:19.480 --> 00:58:23.360 produced no effect. When the hook has caught a thin 849 00:58:23.480 --> 00:58:26.719 twig or even a rigid fiber. The point may be 850 00:58:26.800 --> 00:58:30.159 perceived in from one hour to three hours to have 851 00:58:30.239 --> 00:58:35.039 curled a little inwards, and under favorable circumstances, it curls 852 00:58:35.159 --> 00:58:38.840 round and permanently saizes an object in from eight hours 853 00:58:38.880 --> 00:58:42.440 to ten hours. The hook, when first formed before the 854 00:58:42.519 --> 00:58:46.639 leaf has been downwards, is but little sensitive. If it 855 00:58:46.679 --> 00:58:50.159 catches hold of nothing, it remains open and sensitive for 856 00:58:50.199 --> 00:58:54.840 a long time. Ultimately, the extremity spontaneously and slowly curls 857 00:58:54.880 --> 00:58:58.960 inwards and makes a button like flat spiral coil at 858 00:58:58.960 --> 00:59:02.079 the end of the leaf. One leave was watched and 859 00:59:02.159 --> 00:59:05.320 the hook remained open for thirty three days, but during 860 00:59:05.360 --> 00:59:08.079 the last week the tip had curled so much inwards 861 00:59:08.199 --> 00:59:11.199 that only a very thin twig could have been inserted 862 00:59:11.239 --> 00:59:14.280 within it. As soon as the tip has curled so 863 00:59:14.480 --> 00:59:17.119 much inwards that the hook is converted into a ring, 864 00:59:17.519 --> 00:59:21.280 its sensibility is lost, but as long as it remains open, 865 00:59:21.400 --> 00:59:26.039 some sensibility is retained. Whilst the plant was only about 866 00:59:26.079 --> 00:59:28.960 six inches in height, the leaves four or five in 867 00:59:29.039 --> 00:59:33.559 number were broader than those subsequently produced. Their soft, but 868 00:59:33.800 --> 00:59:38.159 little attenuated tips were not sensitive and did not form hooks, 869 00:59:38.280 --> 00:59:41.920 nor did the stem evolve at this early period of growth. 870 00:59:42.000 --> 00:59:45.519 The plant

can support itself, its climbing powers are not 871 00:59:45.559 --> 00:59:49.400 required and consequently are not developed. So again, the leaves 872 00:59:49.440 --> 00:59:52.599 on the summit of a full grown flowering plant, which 873 00:59:52.599 --> 00:59:55.920 would not require to climb any higher, were not sensitive 874 00:59:56.000 --> 00:59:59.199 and could not clasp the stick. We thus see how 875 00:59:59.239 --> 01:00:05.599 perfect is the economy of nature. Comolinaecea Flagellaria indica. From 876 01:00:05.719 --> 01:00:09.320 dried specimens, it is manifest that this plant climbs exactly 877 01:00:09.480 --> 01:00:13.880 like the gloriosa. A young plant twelve inches in height 878 01:00:13.960 --> 01:00:16.719 and bearing fifteen leaves had not a single leaf as 879 01:00:16.800 --> 01:00:20.320 yet produced into a hook or tendril likee filament, nor 880 01:00:20.360 --> 01:00:25.199 does the stem revolve. Hence this plan acquires its climbing 881 01:00:25.239 --> 01:00:29.639 powers later in life than does the Gloriosa lily. According 882 01:00:29.679 --> 01:00:36.599 to mole page forty one, Ouvlaria melantheacia also climbs like Gloriosa. 883 01:00:37.119 --> 01:00:41.719 These three last named genera are monocotldons, but there is 884 01:00:41.760 --> 01:00:46.719 one dicotoldon, namely Neplenthes, which is ranked by mole page 885 01:00:46.760 --> 01:00:50.079 forty one amongst tendril bearers. And I hear from doctor 886 01:00:50.119 --> 01:00:53.199 Hooker that most of the species climb well at Q. 887 01:00:54.519 --> 01:00:57.320 This is affected by the stalk or midrib between the 888 01:00:57.400 --> 01:01:01.880 leaf and the pitcher, coiling round an support, the twisted 889 01:01:01.920 --> 01:01:06.280 part becomes thicker. But I observed in mister Vetch's hothouse 890 01:01:06.599 --> 01:01:09.079 that the stalk often takes a turn when not in 891 01:01:09.119 --> 01:01:12.639 contact with any object, and that this twisted part is 892 01:01:12.840 --> 01:01:18.760 likewise thickened. Two vigorous young plants of N. Loivis and N. 893 01:01:18.880 --> 01:01:23.679 Distillatoria in my hot house, whilst less than a foot 894 01:01:23.760 --> 01:01:26.840 in height, showed no sensitiveness in their leaves and had 895 01:01:26.880 --> 01:01:31.239 no power of climbing. But when N. Loyvis had grown 896 01:01:31.320 --> 01:01:34.320 to a height of sixteen inches there were signs of 897 01:01:34.360 --> 01:01:38.679 these powers. The young leaves, when first formed, to stand upright, 898 01:01:38.960 --> 01:01:42.599 but soon become inclined. At this period they terminate in 899 01:01:42.679 --> 01:01:46.079 a stalk or filment, with the picture at the extremity 900 01:01:46.159 --> 01:01:51.360 hardly at all developed. The leaves now exhibited slight spontaneous movements, 901 01:01:51.719 --> 01:01:55.280 and when the terminal filaments came into contact with a stick, 902 01:01:55.679 --> 01:01:59.360 they bent slowly round and firmly seized it. But owing 903 01:01:59.360 --> 01:02:02.239 to the subsecut and growth of the leaf, this filament 904 01:02:02.400 --> 01:02:06.199 became after a time quite slap, though still remaining firmly 905 01:02:06.239 --> 01:02:09.480 coiled around the stick. Hence it would appear that the 906 01:02:09.559 --> 01:02:12.519 chief use of the coiling, at least whilst the plant 907 01:02:12.599 --> 01:02:15.239 is young, is to support the pitcher with its load 908 01:02:15.360 --> 01:02:21.320 of secreted fluid. Summary on leaf climbers, plants belonging to 909 01:02:21.360 --> 01:02:24.880 eight families are known to have clasping petioles, and plants 910 01:02:24.920 --> 01:02:30.079 belonging to four families climb by the tips of their leaves. 911 01:02:28.920 --> 01:02:33.800 In all the species observed by me, with one exception, 912 01:02:34.000 --> 01:02:37.280 the young internodes revolve more or less regularly, in some 913 01:02:37.360 --> 01:02:41.800 cases as regularly as those of twining plant. They revolve 914 01:02:41.840 --> 01:02:46.320 at various rates, in most cases rather rapidly. Some few 915 01:02:46.360 --> 01:02:50.400 can ascend by spirally twining round a support. Differently from 916 01:02:50.440 --> 01:02:53.320 most twiners. There is a strong tendency in the same 917 01:02:53.400 --> 01:02:55.960 shoot to revolve first in one and then in an 918 01:02:56.000 --> 01:03:00.000 opposite direction. The object gained by the revolving movement is 919 01:03:00.119 --> 01:03:02.320 to bring the petioles or the tips of the leaves 920 01:03:02.360 --> 01:03:06.679 into contact with surrounded objects, and without this aid the 921 01:03:06.719 --> 01:03:11.119 plant would be much less successful in climbing. With rare exceptions, 922 01:03:11.119 --> 01:03:14.639 the petioles are sensitive only whilst young. They are sensitive 923 01:03:14.679 --> 01:03:17.440 on all sides, but in different degrees in different plants, 924 01:03:17.840 --> 01:03:21.000 and in some species of the Climatis. The several parts 925 01:03:21.039 --> 01:03:25.199 of the same petiole differ much in sensitiveness. The hooked 926 01:03:25.280 --> 01:03:28.639 tips of the leaves of the Gloriosa are sensitive only 927 01:03:28.719 --> 01:03:32.960 on their inner or inferior edge surfaces. The petioles are 928 01:03:33.000 --> 01:03:36.960 sensitive to a touch and to excessively slight continued pressure, 929 01:03:37.400 --> 01:03:40.719 even from a loop of soft thread weighing only the 930 01:03:40.800 --> 01:03:44.840 one sixteenth of a grain four point zero five milligrams, 931 01:03:45.440 --> 01:03:47.760 and there is reason to believe that the thick and 932 01:03:47.960 --> 01:03:51.840 rather stiff petioles of Climatis flamula are sensitive to even 933 01:03:51.960 --> 01:03:55.360 much less weight. If spread over a wide surface. The 934 01:03:55.400 --> 01:03:59.079 petioles always bend towards the size which is pressed or 935 01:03:59.159 -->

01:04:03.199 touched at different rates in different species, sometimes within a 936 01:04:03.280 --> 01:04:08.199 few minutes, but generally after a much longer period. After 937 01:04:08.360 --> 01:04:12.000 temporary contact with any object, the petiole continues to bend 938 01:04:12.039 --> 01:04:16.119 for a considerable time. Afterwards, it slowly becomes straight again 939 01:04:16.199 --> 01:04:20.320 and can then react. A petiole excited by an extremely 940 01:04:20.360 --> 01:04:23.840 slight weight sometimes bends a little, and then becomes accustomed 941 01:04:23.840 --> 01:04:26.840 to the stimius and either bends no more or becomes 942 01:04:26.880 --> 01:04:31.719 straight again, the weight still remaining suspended. Petiles which have 943 01:04:31.800 --> 01:04:35.639 clasped an object for some little time, cannot recover their 944 01:04:35.719 --> 01:04:39.880 original position. After remaining clasped for two or three days, 945 01:04:39.960 --> 01:04:43.480 they generally increase much in thickness, either throughout their whole 946 01:04:43.519 --> 01:04:46.960 diameter or on one side a lowe. They subsequently become 947 01:04:47.079 --> 01:04:50.840 stronger and more woody, sometimes to a wonderful degree, and 948 01:04:50.920 --> 01:04:54.000 in some cases they acquire an internal structure like that 949 01:04:54.239 --> 01:04:58.039 of the stem or axis. The young internodes of the 950 01:04:58.079 --> 01:05:02.079 lofospermam as well as the petules, are sensitive to a touch, 951 01:05:02.480 --> 01:05:06.320 and by their combined movement, seize an object. The flower 952 01:05:06.400 --> 01:05:11.800 peduncles of the Mirandia semprafluorins revolve spontaneously and are sensitive 953 01:05:11.840 --> 01:05:15.400 to a touch, yet are not used for climbing. The 954 01:05:15.519 --> 01:05:18.559 leaves of at least two and probably of most of 955 01:05:18.599 --> 01:05:24.199 the species of Calmatus of Frumeria and Aglumoia spontaneously curve 956 01:05:24.360 --> 01:05:28.000 from side to side like the internodes, and are thus 957 01:05:28.119 --> 01:05:32.639 better adapted to seize distant objects. The petioles of the 958 01:05:32.639 --> 01:05:36.440 perfect leaves of the Tropalium trichlorum, as well as the 959 01:05:36.519 --> 01:05:40.320 tendril like filaments of the plant's whilst young, ultimately move 960 01:05:40.400 --> 01:05:44.000 towards the stem or The supporting stick which they then clasp. 961 01:05:44.719 --> 01:05:49.639 These petioles and filaments also show some tendency to contract spirally. 962 01:05:50.400 --> 01:05:53.719 The tips of the uncut leaves of the Gloriosa, as 963 01:05:53.760 --> 01:05:58.119 they grow old, contract into a spy, flat spire or helix. 964 01:05:58.760 --> 01:06:02.320 These several facts are interesting in relation to true tendrils 965 01:06:02.960 --> 01:06:06.880 with leaf climbers. As with twining plants, the first internodes 966 01:06:06.960 --> 01:06:09.880 which rise from the ground do not, at least in 967 01:06:09.960 --> 01:06:14.360 the cases observed by me, spontaneously revolve, nor are the 968 01:06:14.400 --> 01:06:19.159 petioles or tips of the first formed leaves sensitive. In 969 01:06:19.239 --> 01:06:22.519 certain species of Comatis, the large sizes of the leaves, 970 01:06:22.519 --> 01:06:26.199 together with their habit of revolving, and the extreme sensitiveness 971 01:06:26.239 --> 01:06:29.719 of the petioles, appear to render the revolving movement of 972 01:06:29.760 --> 01:06:34.199 the internodes superfluous, and this latter power has consequently become 973 01:06:34.320 --> 01:06:39.800 much enfabled. In certain species of Tropealium, both the spontaneous 974 01:06:39.840 --> 01:06:43.360 movement of the internodes and the sensitiveness of the petioles 975 01:06:43.400 --> 01:06:46.800 have become much enfeeble, and in one species have been 976 01:06:46.840 --> 01:28:50.920 lost completely. End of Chapter two. Leaves themselves move spontaneously