Transcription complète de Chapter 5

as 33 00:02:15.319 --> 00:02:18.800 certain palms in the New and Old worlds. Even some 34 00:02:18.919 --> 00:02:21.840 climbing roses will ascend the walls of a tall house 35 00:02:22.000 --> 00:02:25.159 if covered with a trellis. How this is affected, I 36 00:02:25.280 --> 00:02:28.280 know not, For the young shoots of one such rose, 37 00:02:28.520 --> 00:02:31.840 when placed in a pot in a window, bent irregularly 38 00:02:31.919 --> 00:02:34.919 towards light during the day and from the light during 39 00:02:34.960 --> 00:02:38.360 the night, like the shoots of any common plant, so 40 00:02:38.400 --> 00:02:41.280 that it is not easy to understand how they could 41 00:02:41.319 --> 00:02:45.680 have got under a trellis close to the wall. Rute climbers. 42 00:02:46.280 --> 00:02:49.080 A good many plants come under this class and are 43 00:02:49.120 --> 00:02:54.240 excellent climbers. One of the most remarkable is the Markgravia umbellata, 44 00:02:54.680 --> 00:02:57.840 the stem of which, in the tropical forests of South America, 45 00:02:57.919 --> 00:03:01.240 as I hear from mister spruce rose in a curiously 46 00:03:01.360 --> 00:03:05.120 flattened manner against the trunks of trees here and there 47 00:03:05.240 --> 00:03:09.240 it puts forth claspers roots which adhere to the trunk, and, 48 00:03:09.360 --> 00:03:12.520 if the latter be slender, completely embrace it. When this 49 00:03:12.680 --> 00:03:15.680 plant has climbed to the light, it produces free branches 50 00:03:15.719 --> 00:03:20.159 with rounded stems clad with sharp, pointed leaves, wonderfully different 51 00:03:20.199 --> 00:03:22.520 in appearance from those borne by the stem as it 52 00:03:22.599 --> 00:03:26.000 remains adherent. This surprising difference in the leaves I have 53 00:03:26.159 --> 00:03:29.439 also observed in a plant of Margravia dubia in my 54 00:03:29.520 --> 00:03:33.759 hothouse roof climbers, as far as I have seen, namely 55 00:03:33.800 --> 00:03:39.960 the Ivy, Hederahalia, Phycus ripens and F. Barbatas, have no 56 00:03:40.080 --> 00:03:42.919 power of movement, not even from the light to the dark. 57 00:03:43.680 --> 00:03:48.360 As previously stated, the Hoya carnosa as clepidacia is a 58 00:03:48.400 --> 00:03:52.039 spiral twiner and likewise adheres by rootlets even to a 59 00:03:52.120 --> 00:03:57.759 flat wall. The tendril bearing Bignonia tridiana admits roots which 60 00:03:57.840 --> 00:04:01.560 curve half round and adhere to thin stee The Tacoma 61 00:04:01.680 --> 00:04:07.479 ratiican's Bignonacea, which is closely allied to many spontaneously revolving species, 62 00:04:07.719 --> 00:04:12.319 climbs by rootlets. Nevertheless, its young shoots apparently move about 63 00:04:12.400 --> 00:04:14.800 more than can be counted for by the varying action 64 00:04:14.879 --> 00:04:19.120 of the light. I have not closely observed many root climbers, 65 00:04:19.319 --> 00:04:23.600 but can give one curious fact. Vicus rappens climbs up 66 00:04:23.600 --> 00:04:26.600 a wall just like Ivy, and when the young rootlets 67 00:04:26.600 --> 00:04:29.480 are made to press lightly on slips of glass, they 68 00:04:29.560 --> 00:04:33.000 emit after about a week's interval. As I observe several 69 00:04:33.079 --> 00:04:37.480 times minute drops of clear fluid, not in the least milky, 70 00:04:37.600 --> 00:04:41.279 like that exuded from a wound. This fluid is slightly vicid, 71 00:04:41.560 --> 00:04:45.040 but cannot be drawn out into threads. It has the 72 00:04:45.079 --> 00:04:49.120 remarkable property of not soon drying. A drop about the 73 00:04:49.160 --> 00:04:52.839 size of half a pin's head was slightly spread out 74 00:04:52.920 --> 00:04:56.000 on glass, and I scattered on it some minute grains 75 00:04:56.000 --> 00:04:59.279 of sand. The glass was left exposed in a drawer 76 00:04:59.399 --> 00:05:02.360 during hot and dry weather, and if the fluid had 77 00:05:02.399 --> 00:05:05.800 been water, it would certainly have dried in a few minutes. 78 00:05:06.240 --> 00:05:09.920 But it remained fluid closely surrounding each grain of sand 79 00:05:10.040 --> 00:05:13.279 during one hundred and twenty eight days. How much longer 80 00:05:13.319 --> 00:05:17.079 it would have remained I cannot say. Some other rootlets 81 00:05:17.120 --> 00:05:19.800 were left in contact with the glass for about ten 82 00:05:19.920 --> 00:05:23.160 days or a fortnight, and the drops of secreted fluid 83 00:05:23.399 --> 00:05:26.439 were now rather larger and so visied that they could 84 00:05:26.439 --> 00:05:29.839 be drawn out into threads. Some other rootlets were left 85 00:05:29.879 --> 00:05:33.639 in contact during twenty three days, and these were firmly 86 00:05:33.680 --> 00:05:37.000 cemented to the glass. Hence we may conclude that the 87 00:05:37.040 --> 00:05:41.199 rootlets first secrete a slightly visited fluid subsequently absorbed the 88 00:05:41.279 --> 00:05:44.319 watery parts. For we have seen that the fluid will 89 00:05:44.319 --> 00:05:48.720 not dry by itself and ultimately leave a cement. When 90 00:05:48.759 --> 00:05:51.519 the rootlets were torn from the glass. Atoms of yellowish 91 00:05:51.600 --> 00:05:55.000 matter were left on it, which were partly dissolved by 92 00:05:55.000 --> 00:05:58.279 a drop of bi sulfide of carbon, and this extremely 93 00:05:58.399 --> 00:06:02.000 volatile fluid was rendered much less volatile by what it 94 00:06:02.079 --> 00:06:06.079 had dissolved, as the bisulfide of carbon has a strong 95 00:06:06.160 --> 00:06:10.319 power of softening endured Chao chok. I soaked in it 96 00:06:10.600 --> 00:06:13.920 during a short time several rootlets of a plant which 97 00:06:13.920 --> 00:06:17.639 had grown up a plastered wall, and I then found 98 00:06:17.800 --> 00:06:23.600 many extremely thin threads of transparent, not vised excessively elastic 99 00:06:23.720 --> 00:06:29.600 matter precisely like kaochok, attached

to two sets of rootlets 100 00:06:29.639 --> 00:06:33.839 on the same branch. These threads proceeded from the bark 101 00:06:33.879 --> 00:06:36.279 of the rootlet at one end, and at the other 102 00:06:36.439 --> 00:06:39.959 end were firmly attached to particles of silex or mortar 103 00:06:40.000 --> 00:06:43.519 from the wall. There could be no mistake in this observation, 104 00:06:44.000 --> 00:06:46.199 as I played with the threads for a long time 105 00:06:46.319 --> 00:06:49.800 under the microscope, drawing them out with my dissecting needle 106 00:06:49.879 --> 00:06:53.480 and letting them spring back. Yet I looked repeatedly at 107 00:06:53.519 --> 00:06:57.439 other rootlets similarly treated, and could never again discover these 108 00:06:57.439 --> 00:07:01.240 elastic threads. I therefore inferred that the branch in question 109 00:07:01.519 --> 00:07:04.399 must have been slightly moved from the wall at some 110 00:07:04.519 --> 00:07:07.519 critical period whilst the secretion was in the act of 111 00:07:07.600 --> 00:07:11.959 drying through the absorption of its watery parts. The genus 112 00:07:12.000 --> 00:07:15.759 Pycus abounds with chaochok, and we may conclude from the 113 00:07:15.800 --> 00:07:19.319 facts just given that this substance, at first in solution 114 00:07:19.480 --> 00:07:23.639 and ultimately modified into an unelastic cement, is used by 115 00:07:23.639 --> 00:07:27.079 the Phycus ripens to cement its rootlets to any surface 116 00:07:27.199 --> 00:07:30.759 which it ascends. Whether other plants which climb by their 117 00:07:30.800 --> 00:07:34.240 rootlets emit any cement, I do not know. But the 118 00:07:34.319 --> 00:07:38.279 rootlets of the ivy placed against glass rarely adhere to it, 119 00:07:38.600 --> 00:07:42.680 yet secreted a little yellowish matter. I may add that 120 00:07:42.720 --> 00:07:46.319 the rootlets of the Margravia dubia can adhere firmly to 121 00:07:46.399 --> 00:07:52.360 smooth painted wood. Vanilla aromatica emits aerial roots a foot 122 00:07:52.399 --> 00:07:56.160 in length, which point straight down to the ground. According 123 00:07:56.199 --> 00:08:00.120 to Mole, page forty nine, these crawl into crevices when 124 00:08:00.160 --> 00:08:03.040 when they meet with a thin support, wind round it, 125 00:08:03.399 --> 00:08:07.279 as do tendrils. A plant which I kept was young 126 00:08:07.439 --> 00:08:10.839 and did not form long roots, but on placing thin 127 00:08:10.920 --> 00:08:13.920 sticks in contact with them, they certainly bent a little 128 00:08:13.920 --> 00:08:16.680 to that side. In the course of about a day, 129 00:08:17.040 --> 00:08:19.720 and adhered by their rootlets to the wood, But they 130 00:08:19.720 --> 00:08:22.800 did not bend quite round the sticks, and afterwards they 131 00:08:22.800 --> 00:08:26.560 re pursued their downward course. It is probable that these 132 00:08:26.560 --> 00:08:29.800 slight movements of the root are due to the quicker 133 00:08:29.839 --> 00:08:32.720 growth of the side exposed to the light in comparison 134 00:08:32.759 --> 00:08:35.559 with the other, and not because the roots are sensitive 135 00:08:35.600 --> 00:08:39.639 to contact in the same manner as true tendrils. According 136 00:08:39.679 --> 00:08:43.559 to Mole, the rootlets of certain species of Lycopodium act 137 00:08:43.679 --> 00:08:50.279 as tendrils. Concluding remarks on climbing plants, plants become climbers 138 00:08:50.320 --> 00:08:52.799 in order, as it may be presumed, to reach the 139 00:08:52.879 --> 00:08:55.440 light and to expose a large surface of their leaves 140 00:08:55.480 --> 00:08:57.879 to its action and to that of the free air. 141 00:08:58.639 --> 00:09:02.399 This is effected by climbs with wonderfully little expenditure of 142 00:09:02.519 --> 00:09:06.519 organized matter in comparison with trees, which have to support 143 00:09:06.559 --> 00:09:10.320 a load of heavy branches by a massive trunk. Hence, 144 00:09:10.440 --> 00:09:13.480 no doubt it arises that there are so many climbing 145 00:09:13.519 --> 00:09:16.320 plants in all quarters of the world, belonging to so 146 00:09:16.440 --> 00:09:21.240 many different orders. These plants have then arranged under four classes, 147 00:09:21.279 --> 00:09:26.000 disregarding those which merely scramble over bushes without any special aid. 148 00:09:26.759 --> 00:09:30.080 Hook climbers are the least efficient of all, at least 149 00:09:30.159 --> 00:09:33.120 in our temperate countries, and can climb only in the 150 00:09:33.159 --> 00:09:37.399 midst of an entangled mass of vegetation. Root climbers are 151 00:09:37.440 --> 00:09:41.639 excellently adapted to ascend naked faces of rock or trunks 152 00:09:41.639 --> 00:09:45.559 of trees. When, however, they climb trunks, they are compelled 153 00:09:45.559 --> 00:09:48.240 to keep much in the shade. They cannot pass from 154 00:09:48.240 --> 00:09:51.120 branch to branch and thus cover the whole summit of 155 00:09:51.120 --> 00:09:54.960 a tree, for their rootlets require long, continued and close 156 00:09:55.039 --> 00:09:58.679 contact with a steady surface in order to adhere. The 157 00:09:58.759 --> 00:10:02.519 two great classes of twiners and of plants with sensitive organs, 158 00:10:02.879 --> 00:10:07.000 namely leaf climbers and tendril bearers, taken together, far exceed 159 00:10:07.039 --> 00:10:09.879 in number and in the perfection of their mechanism. The 160 00:10:09.960 --> 00:10:13.559 climbers of the two first classes, those which have the 161 00:10:13.600 --> 00:10:17.480 power of spontaneously revolving and of grasping objects with which 162 00:10:17.519 --> 00:10:21.000 they come in contact, pass easily from branch to branch 163 00:10:21.279 --> 00:10:26.519 and securely ramble over a wide sunlit surface. The divisions 164 00:10:26.559 --> 00:10:30.879 containing twining plants, leaf climbers, and tendril bearers graduate to

165 00:10:30.919 --> 00:10:34.440 a certain extent into one another. And nearly all have 166 00:10:34.519 --> 00:10:39.480 the same remarkable power of spontaneously revolving. Does this gradeation 167 00:10:39.759 --> 00:10:42.679 it may be asked to indicate that plants belonging to 168 00:10:42.759 --> 00:10:46.759 one subdivision have actually passed during lapse of ages, or 169 00:10:46.879 --> 00:10:51.120 can pass from one state to the other, as for instance, 170 00:10:51.200 --> 00:10:55.399 any tendril bearing plant assumed its present structure without having 171 00:10:55.480 --> 00:10:59.399 previously existed as a leaf climber or a twiner. If 172 00:10:59.399 --> 00:11:02.559 we consider leaf climbers alone, the idea that they were 173 00:11:02.639 --> 00:11:08.320 primortively twiners is forcibly suggested. The internodes of all, without exception, 174 00:11:08.720 --> 00:11:12.320 revolve in exactly the same manner as twiners. Some few 175 00:11:12.440 --> 00:11:16.440 can still twine well, and many others in an imperfect manner. 176 00:11:17.159 --> 00:11:20.919 Several leaf climbing genera are closely allied to other genera 177 00:11:20.960 --> 00:11:24.799 which are simple twiners. It should also be observed that 178 00:11:24.879 --> 00:11:28.159 the possession of leaves with sensitive petioles and with the 179 00:11:28.200 --> 00:11:32.360 consequent power of clasping the object, would be of comparatively 180 00:11:32.440 --> 00:11:36.360 little use to a plant unless associated with revolving internodes 181 00:11:36.639 --> 00:11:39.639 by which the leaves are brought into contact with the support, 182 00:11:40.080 --> 00:11:43.279 although no doubt a scrambling plant would be apt. As 183 00:11:43.320 --> 00:11:46.759 Professor Jeger has remarked to rest on other plants by 184 00:11:46.799 --> 00:11:50.799 its leave. On the other hand, revolving internodes without any 185 00:11:50.840 --> 00:11:54.320 other aid suffice to give the power of climbing, so 186 00:11:54.360 --> 00:11:57.759 that it seems probable that leaf climbers were in most 187 00:11:57.840 --> 00:12:02.159 cases at first twiners and subsequently became capable of grasping 188 00:12:02.159 --> 00:12:05.399 a support. And this, as we shall see, is a 189 00:12:05.440 --> 00:12:10.440 great additional advantage. From analogous reasons, it is probable that 190 00:12:10.480 --> 00:12:14.960 all tendril bearers were primordially twiners, that is, our descendants 191 00:12:14.960 --> 00:12:18.399 of plants having this power and habit. For the internodes 192 00:12:18.440 --> 00:12:21.600 of the majority revolve, and in a few species the 193 00:12:21.679 --> 00:12:26.240 flexible stem still retained the capacity of spirally twining round 194 00:12:26.279 --> 00:12:30.519 and upright. Stick tentril bearers have undergone much more modification 195 00:12:30.639 --> 00:12:33.840 than leaf climbers. Hence it is not surprising that their 196 00:12:33.879 --> 00:12:37.600 supposed primordial habits of revolving and twining have been more 197 00:12:37.639 --> 00:12:41.159 frequently lost or modified than in the case of leaf climbers. 198 00:12:41.919 --> 00:12:45.000 The three great tendril bearing families in which this loss 199 00:12:45.000 --> 00:12:50.200 has occurred in the most marked manner of the Kukurbetasia, Passifloracia, 200 00:12:50.320 --> 00:12:54.240 and Vitasia. In the first, the internodes revolve, but I 201 00:12:54.279 --> 00:12:57.799 have heard of no twining form, with the exception according 202 00:12:57.799 --> 00:13:02.480 to Palm page twenty nine fifty two of Momordica balsamina, 203 00:13:03.159 --> 00:13:07.159 and this is only an imperfect twiner. In the two 204 00:13:07.399 --> 00:13:10.600 other families I can hear of no twiners, and the 205 00:13:10.600 --> 00:13:14.279 internodes rarely have the power of revolving, this power being 206 00:13:14.320 --> 00:13:19.759 confined to the tendrils. The internodes, however, of Passiflora gracillus, 207 00:13:19.799 --> 00:13:22.639 have the power in a perfect manner, and those of 208 00:13:22.679 --> 00:13:26.000 the common vine in an imperfect manner, so that at 209 00:13:26.080 --> 00:13:28.960 least a trace of the supposed primordial habit has been 210 00:13:29.039 --> 00:13:33.159 retained by some members of all the larger tendril bearing groups. 211 00:13:34.440 --> 00:13:37.320 On the view here given, it may be asked why 212 00:13:37.360 --> 00:13:42.000 had the species which were aboriginally twiners been converted into 213 00:13:42.039 --> 00:13:46.440 so many groups into leaf climbers or tendril bearers. Of 214 00:13:46.600 --> 00:13:49.799 what advantage has this been to them? Why did they 215 00:13:49.840 --> 00:13:54.360 not remain simple twiners. We can see several reasons. It 216 00:13:54.480 --> 00:13:56.960 might be an advantage to a plant to acquire a 217 00:13:57.000 --> 00:14:01.440 thicker stem with short internodes bearing many or large leaves, 218 00:14:01.480 --> 00:14:05.600 and such stems are ill fitted for twining. Anyone who 219 00:14:05.600 --> 00:14:08.399 will look during windy weather at twining plants will see 220 00:14:08.440 --> 00:14:11.919 that they are easily blown from their support. Not so 221 00:14:12.159 --> 00:14:15.240 with tendril bearers or leaf climbers, where they quickly and 222 00:14:15.399 --> 00:14:18.799 firmly grasp the support by a much more efficient kind 223 00:14:18.919 --> 00:14:22.759 of movement. In those plants which still twine but at 224 00:14:22.799 --> 00:14:26.480 the same time possess tendrils or sensitive petioles, as some 225 00:14:26.600 --> 00:14:31.919 species of Bignonia hermatus and Tropelium, it can readily be 226 00:14:31.960 --> 00:14:36.080 observed how incomparably better they grasp an upright stick than 227 00:14:36.120 --> 00:14:40.399 do simple twiners. Tendrils from possessing this power of grasping 228 00:14:40.399 --> 00:14:43.480 an object can be made long

and thin, so that 229 00:14:43.600 --> 00:14:47.559 little organic matter is inxibended in their development, and yet 230 00:14:47.600 --> 00:14:51.879 they sweep a wide circle in search of support. Tendril 231 00:14:51.919 --> 00:14:55.440 Bearers can from their first growth ascend along the outer 232 00:14:55.559 --> 00:14:59.039 branches of any neighboring bush, and they are thus always 233 00:14:59.159 --> 00:15:03.039 fully exposed to the light. Twiners, on the contrary, are 234 00:15:03.039 --> 00:15:06.440 best fitted to ascend bare stems and generally have to 235 00:15:06.480 --> 00:15:10.720 start in the shade. Within tall and dense tropical forests. 236 00:15:10.879 --> 00:15:14.480 Twining plants would probably succeed better than most kinds of 237 00:15:14.559 --> 00:15:18.039 tendril bearers, but the majority of twiners, at least in 238 00:15:18.080 --> 00:15:21.399 our tempered regions, from the nature of their revolving movement, 239 00:15:21.759 --> 00:15:25.679 cannot ascend thick trunks, whereas this can be affected by 240 00:15:25.720 --> 00:15:28.799 tendril bearers if the trunks are branched or bare twigs, 241 00:15:29.120 --> 00:15:32.600 and by some species if the bark is rugged. The 242 00:15:32.679 --> 00:15:35.320 advantage gained by climbing is to reach the light and 243 00:15:35.399 --> 00:15:39.000 free air with as little expenditure of organic matter as possible. 244 00:15:39.720 --> 00:15:42.919 Now with twining plants, the stem is much longer than 245 00:15:43.000 --> 00:15:46.320 is absolutely necessary. For instance, I measured the stem of 246 00:15:46.360 --> 00:15:49.360 a kidney bean, which had ascended exactly two feet in height, 247 00:15:49.679 --> 00:15:52.639 and it was three feet in length. The stem of 248 00:15:52.639 --> 00:15:54.799 a pea, on the other hand, which had ascended to 249 00:15:54.840 --> 00:15:57.320 the same height by the aid of its tendrils, was 250 00:15:57.360 --> 00:16:00.960 but little longer than the height reached. That this saving 251 00:16:01.000 --> 00:16:03.799 of the stem is really an advantage to climbing plants. 252 00:16:04.120 --> 00:16:07.159 I infer from the species that still twine, but are 253 00:16:07.200 --> 00:16:11.559 aided by clasping petioles or tendrils, generally making more open 254 00:16:11.639 --> 00:16:16.240 spires than those made by symbol twiners. Moreover, the plants 255 00:16:16.360 --> 00:16:19.720 thus aided, after taking one or two turns in one direction, 256 00:16:20.120 --> 00:16:23.639 generally ascend for a space straight and then reverse the 257 00:16:23.679 --> 00:16:27.440 direction of their spire. By this means they ascend to 258 00:16:27.480 --> 00:16:30.799 a considerably greater height with the same length of stem 259 00:16:31.120 --> 00:16:34.000 than would otherwise have been possible, and they do this 260 00:16:34.120 --> 00:16:37.200 with safety, as they secure themselves at intervals by their 261 00:16:37.240 --> 00:16:41.200 clasping petioles or tendrils. We have seen that the tendrils 262 00:16:41.240 --> 00:16:45.080 consist of various organs in a modified state, namely leaves, 263 00:16:45.159 --> 00:16:49.559 flower peduncles, branches, and perhaps stipules. With respect to leaves, 264 00:16:49.679 --> 00:16:53.279 the evidence of their modification is ample. In young plants 265 00:16:53.320 --> 00:16:57.799 of Ignonia. The lower leaves often remain quite unchanged, whilst 266 00:16:57.840 --> 00:17:02.480 the upper ones have their terminal leaflets converted into perfect tendrils. 267 00:17:02.960 --> 00:17:06.480 In ecromycarpus, I have seen a single lateral branch of 268 00:17:06.519 --> 00:17:11.200 a tendril replaced by a perfect leaflet. In Visiersativa, on 269 00:17:11.240 --> 00:17:15.559 the other hand, leaflets are sometimes replaced by tendril branches, 270 00:17:15.920 --> 00:17:19.279 and many other such cases could be given. But he 271 00:17:19.359 --> 00:17:22.759 who believes in the slow modification of species will not 272 00:17:22.839 --> 00:17:26.480 be content simply to ascertain the homological nature of different 273 00:17:26.559 --> 00:17:29.240 kinds of tendrils. He will wish to learn as far 274 00:17:29.279 --> 00:17:33.160 as as possible by what actual steps leaves, flower, peduncles, 275 00:17:33.160 --> 00:17:36.559 et cetera, have had their functions wholly changed and have 276 00:17:36.640 --> 00:17:40.599 come to serve merely as prehensile organs. In the whole 277 00:17:40.640 --> 00:17:44.119 group of leaf climbers, abundant evidence has been given that 278 00:17:44.200 --> 00:17:47.599 an organ still subserving the functions of a leaf may 279 00:17:47.640 --> 00:17:51.640 become sensitive to a touch and thus grasp an adjoining object. 280 00:17:52.400 --> 00:17:56.200 With several leaf climbers, the true leaves spontaneously revolve, and 281 00:17:56.279 --> 00:17:59.920 their petioles, after clasping the support, grow thicker and strong. 282 00:18:00.839 --> 00:18:03.960 We thus see that leaves may acquire all the leading 283 00:18:04.039 --> 00:18:09.359 and characteristic qualities of tendrils, namely sensitiveness, spontaneous movement, and 284 00:18:09.480 --> 00:18:14.119 subsequently increased strength. If their blades or lamina were to abort, 285 00:18:14.400 --> 00:18:18.079 they would form true tendrils, and this process of abortion 286 00:18:18.279 --> 00:18:21.240 we can follow every step until no trace of the 287 00:18:21.240 --> 00:18:25.680 original nature of the tendril is left. In Buttisia calmatis, 288 00:18:25.920 --> 00:18:29.920 the tendril in shape and color closely resembles the petiole 289 00:18:30.000 --> 00:18:33.279 of one of the ordinary leaves, together with the mid 290 00:18:33.400 --> 00:18:36.920 ribs of the leaflets, but the vestiges of the laminae 291 00:18:37.119 --> 00:18:41.920 are still occasionally retained. In four genera of the Fumeriacea, 292 00:18:42.359 --> 00:18:46.400 we can follow the

whole process of transformation. The terminal 293 00:18:46.480 --> 00:18:51.000 leaflets of the leaf climbing Fumaria officionalus are not smaller 294 00:18:51.039 --> 00:18:54.279 than the other leaflets. Those of the leaf climbing and 295 00:18:54.400 --> 00:19:00.440 Lumiacerosa are greatly reduced. Those of Corridalus claviculata, a plant 296 00:19:00.440 --> 00:19:03.119 which may indifferently be called a leaf climber or a 297 00:19:03.119 --> 00:19:07.599 tendril bearer, are either reduced to microscopical dimensions or have 298 00:19:07.680 --> 00:19:11.119 their blade wholly aborted, so that this plant is actually 299 00:19:11.160 --> 00:19:14.720 in a state of transition. And finally, in the dicentra, 300 00:19:15.079 --> 00:19:20.160 the tendrils are perfectly characterized. If therefore we could behold 301 00:19:20.519 --> 00:19:24.279 at the same time all the progenitors of Dicentra, we 302 00:19:24.319 --> 00:19:27.680 should almost certainly see a series like that now exhibited 303 00:19:27.920 --> 00:19:32.640 by the above named three genera. In Tropalium trichlorum we 304 00:19:32.720 --> 00:19:35.839 have another kind of passage, for the leaves which are 305 00:19:35.880 --> 00:19:39.079 first formed on the young stems are entirely destitute of 306 00:19:39.160 --> 00:19:43.279 laminae and must be called tendrils, whilst the latter formed 307 00:19:43.359 --> 00:19:47.720 leaves have well developed laminae. In all cases, the acquirement 308 00:19:47.920 --> 00:19:51.119 of sensitiveness by the mid rips of the leaves appear 309 00:19:51.240 --> 00:19:54.240 to stand in some close relation with the abortion of 310 00:19:54.279 --> 00:19:59.200 their laminae or blades. On the view here given, leaf 311 00:19:59.240 --> 00:20:04.359 climbers or primordially twiners and tendril bearers when formed of 312 00:20:04.440 --> 00:20:09.640 modified leaves, were primordially leaf climbers. The latter therefore are 313 00:20:09.720 --> 00:20:13.440 intermediate in nature between twiners and tendril bearers, and ought 314 00:20:13.480 --> 00:20:17.400 to be related to both. This is the case. Thus 315 00:20:17.519 --> 00:20:22.839 the several leaf climbing species of Antineae of Solanum, Coculus 316 00:20:23.000 --> 00:20:26.759 and Gloriosa have within the same family, and even within 317 00:20:26.799 --> 00:20:31.880 the same genus, relatives which are twiners. In the genus Micania, 318 00:20:32.200 --> 00:20:36.279 there are leaf climbing and twining species. The leaf climbing 319 00:20:36.319 --> 00:20:40.079 species of Climatis are very closely allied to the tendril 320 00:20:40.119 --> 00:20:45.160 bearing Naravelia. The Femiaica include closely allied genera which are 321 00:20:45.240 --> 00:20:50.160 leaf climbers and tendril bearers. Lastly, a species of Bignonia 322 00:20:50.440 --> 00:20:53.079 is at the same time both a leaf climber and 323 00:20:53.160 --> 00:20:57.079 a tendril bearer, and other closely allied species are twiners.

324 00:20:58.039 --> 00:21:02.519 Tendrils of another kind consist of modified flower peduncles. In 325 00:21:02.680 --> 00:21:07.079 this case, we likewise have many interesting transitional states. The 326 00:21:07.200 --> 00:21:10.960 common vine, not to mention the Cardiospermum gives us every 327 00:21:11.039 --> 00:21:14.759 possible gradation between a perfectly developed tendril and a flower 328 00:21:14.759 --> 00:21:18.839 peduncle covered with flowers, yet furnished with a branch forming 329 00:21:18.960 --> 00:21:23.119 the flower tendril when the latter itself bears a few flowers, 330 00:21:23.400 --> 00:21:26.559 as we know sometimes is the case, and still retains 331 00:21:26.599 --> 00:21:29.400 the power of clasping a support. We see an early 332 00:21:29.440 --> 00:21:32.839 condition of all those tendrils which have been formed by 333 00:21:32.839 --> 00:21:37.480 the modification of flower peduncles. According to Mole and others, 334 00:21:37.839 --> 00:21:42.359 some tendrils consist of modified branches. I have not observed 335 00:21:42.400 --> 00:21:46.000 any such cases and know nothing of their transitional states, 336 00:21:46.400 --> 00:21:50.039 but these have been fully described by Fritz Muller. The 337 00:21:50.079 --> 00:21:54.680 genus Bufospermum also shows us how such a transition is possible, 338 00:21:55.000 --> 00:22:00.319 for its branches spontaneously revolved and are sensitive to contact. Hence, 339 00:22:00.400 --> 00:22:02.279 if the leaves on some of the branches of the 340 00:22:02.359 --> 00:22:06.640 Lofus firmam were to abort, these branches would be converted 341 00:22:06.720 --> 00:22:10.880 into true tendrils. Nor is there anything improbable in certain 342 00:22:10.920 --> 00:22:15.839 branches alone being thus modified, whilst others remain unaltered. For 343 00:22:16.000 --> 00:22:19.559 we have seen with certain varieties of Phasiolus that some 344 00:22:19.640 --> 00:22:23.240 of the branches are thin, flexible and twine, whilst others 345 00:22:23.279 --> 00:22:26.039 on the same plant are stiff and have no such power. 346 00:22:26.960 --> 00:22:30.039 If we inquire how a petiole, a branch or flower 347 00:22:30.079 --> 00:22:33.680 pedungle first became sensitive to a touch and acquired the 348 00:22:33.720 --> 00:22:37.079 power of bending towards the touched side, we get no 349 00:22:37.240 --> 00:22:42.759 certain answer. Nevertheless, an observation by Hoffmeister well deserves attention, 350 00:22:43.359 --> 00:22:46.480 namely that the shoots and leaves of all plants, whilst young, 351 00:22:46.920 --> 00:22:51.559 move after being shaken. Kerner also finds, as we have seen, 352 00:22:51.799 --> 00:22:54.599 that the flower peduncles of a large number of plants, 353 00:22:54.680 --> 00:22:58.079 if shaken or gently rubbed, bend to this side, and 354 00:22:58.240 --> 00:23:02.319 it is young petioles and ten whatever their homological nature 355 00:23:02.359 --> 00:23:06.119 may be,

which move on being touched. It thus appears 356 00:23:06.160 --> 00:23:09.720 that climbing plants have utilized and perfected a widely distributed 357 00:23:09.759 --> 00:23:13.519 and incipient capacity, which capacity, as far as we can see, 358 00:23:13.599 --> 00:23:17.200 is of no service to ordinary plants. If we further 359 00:23:17.319 --> 00:23:20.960 inquire how the stems, petules, tendrils, and flower peduncles of 360 00:23:21.000 --> 00:23:25.920 climbing plants first acquired their power of spontaneously revolving, or 361 00:23:26.079 --> 00:23:29.640 to speak more accurately, of successively bending to all points 362 00:23:29.680 --> 00:23:33.039 of the compass, we are again silenced, or at least 363 00:23:33.079 --> 00:23:37.160 can only remark that the power of moving both spontaneously 364 00:23:37.200 --> 00:23:40.759 and from various stimulants is far more common with plants 365 00:23:40.920 --> 00:23:43.200 than is generally supposed to be the case by those 366 00:23:43.200 --> 00:23:46.839 who have not attended to the subject. I have given 367 00:23:46.920 --> 00:23:51.200 one remarkable instance, namely that of the Morandia semper florins, 368 00:23:51.640 --> 00:23:55.200 the young flower peduncles of which spontaneously revolve in very 369 00:23:55.240 --> 00:23:59.279 small circles and bend when gently rubbed to the touched side. 370 00:23:59.599 --> 00:24:02.480 Yet this plant certainly does not profit by these two 371 00:24:02.519 --> 00:24:07.440 feebly developed powers. A rigorous examination of other young plants 372 00:24:07.559 --> 00:24:11.799 would probably show slight spontaneous movement in their stems, petioles 373 00:24:11.880 --> 00:24:16.279 or peduncles, as well as sensitiveness to touch. We see 374 00:24:16.319 --> 00:24:19.359 at least that the Morandia might, by a little augmentation 375 00:24:19.480 --> 00:24:22.200 of the powers which it possesses, come first to grasp 376 00:24:22.279 --> 00:24:25.920 the support bias flower peduncles, and then, by the abortion 377 00:24:26.039 --> 00:24:29.119 of some of its flowers, as with Vitus or cardiospermam, 378 00:24:29.440 --> 00:24:34.079 acquire perfect tendrils. There is one other interesting point which 379 00:24:34.119 --> 00:24:37.720 deserves notice. We have seen that some tendrils owe their 380 00:24:37.759 --> 00:24:41.440 origin to modified leaves, and others to modified flower peduncles, 381 00:24:41.759 --> 00:24:45.000 so that some are folia and others axial in their nature. 382 00:24:45.720 --> 00:24:47.920 It might therefore have been expected that they would have 383 00:24:48.000 --> 00:24:51.400 presented some difference in function. This is not the case. 384 00:24:51.920 --> 00:24:55.119 On the contrary, they present the most complete identity in 385 00:24:55.160 --> 00:25:00.440 their several characteristic powers. Tendrils of both kinds spontaneously revolve 386 00:25:00.519 --> 00:25:04.200 at about the same rate. Both when touched, bent quickly 387 00:25:04.240 --> 00:25:07.160 to the touched side, and afterwards recover themselves and are 388 00:25:07.200 --> 00:25:11.319 able to act again. In both the sensitiveness is either 389 00:25:11.359 --> 00:25:14.519 confined to one side or extends all round the tendril. 390 00:25:15.160 --> 00:25:18.440 Both are either attracted or repelled by the light. The 391 00:25:18.519 --> 00:25:21.880 latter property is seen in the foliar tendrils of Bignonia 392 00:25:21.920 --> 00:25:26.799 capriolata and in the axial tendrils of Amphlopsis. The tips 393 00:25:26.799 --> 00:25:30.000 of the tendrils in these two plants become, after contact 394 00:25:30.160 --> 00:25:33.559 enlarged into disks, which are at first adhesive by the 395 00:25:33.599 --> 00:25:37.880 secretion of some cement. Tendrils of both kinds, soon after 396 00:25:37.960 --> 00:25:42.160 grasping the support contract spiderly. They then increase greatly in 397 00:25:42.240 --> 00:25:46.200 thickness and strength. When we add to these several points 398 00:25:46.240 --> 00:25:50.480 of identity the fact that the petule of the Solanum jasminides. 399 00:25:50.759 --> 00:25:53.279 After it has classed, the support assumes one of the 400 00:25:53.279 --> 00:25:57.079 most characteristic features of the axis, namely a closed ring 401 00:25:57.119 --> 00:26:00.319 of woody vessels. We can hardly avoid asci whether the 402 00:26:00.359 --> 00:26:04.240 fundamental difference between folia and axial organs can be of 403 00:26:04.319 --> 00:26:08.440 so fundamental a nature as is generally supposed. We have 404 00:26:08.480 --> 00:26:11.079 attempted to trace some of the stages of the genesis 405 00:26:11.079 --> 00:26:14.519 of climbing plants. But during the endless fluctuations of the 406 00:26:14.559 --> 00:26:18.039 conditions of life to which all organic beings have been exposed, 407 00:26:18.400 --> 00:26:21.000 it might be expected that some climbing plants would have 408 00:26:21.079 --> 00:26:24.279 lost the habit of climbing. In the cases given of 409 00:26:24.359 --> 00:26:28.599 certain South African plants belonging to great twining families, which 410 00:26:28.599 --> 00:26:31.640 in their native country never twine, but we assume this 411 00:26:31.759 --> 00:26:34.599 habit when cultivated in England. We have a case in 412 00:26:34.720 --> 00:26:39.000 point in the leaf climbing Climatis flamula, and in the 413 00:26:39.000 --> 00:26:41.839 tender bearing vine. We see no loss in the power 414 00:26:41.839 --> 00:26:44.799 of climbing, but only a remnant of the revolving power, 415 00:26:44.799 --> 00:26:48.000 which is indispensable to all climbers, and it is so 416 00:26:48.119 --> 00:26:52.160 common as well as so advantaged to most climbers. In 417 00:26:52.200 --> 00:26:55.960 Tacoma raticans, one of the bignoniasia. We see a last 418 00:26:56.000 --> 00:26:59.200 and doubtful trace of the power of the revolving with 419 00:26:59.279 --> 00:27:03.119 respect

to the abortion of tendrils. Certain cultivated varieties of 420 00:27:03.200 --> 00:27:07.759 Kucurbita popos have, according to Nauden, either quite lost these 421 00:27:07.880 --> 00:27:12.079 organs or bear semi monstrous representatives of them. In my 422 00:27:12.200 --> 00:27:15.559 limited experience, I have met with only one apparent instance 423 00:27:15.599 --> 00:27:19.279 of their natural suppression, namely in the common being. All 424 00:27:19.359 --> 00:27:23.279 the other species of vissier I believe tendril bearers, but 425 00:27:23.480 --> 00:27:26.039 the being is stiff enough to support its own stem. 426 00:27:26.359 --> 00:27:28.559 And in this species, at the end of the petiole, 427 00:27:28.640 --> 00:27:32.319 where according to analogy, a tendril ought to have existed, 428 00:27:32.839 --> 00:27:35.759 a small pointed filament projects about a third of an 429 00:27:35.759 --> 00:27:40.319 engine length, and which is probably the rudiment of a tendril. 430 00:27:40.440 --> 00:27:42.960 This may be the more safely inferred, as in young 431 00:27:43.000 --> 00:27:47.319 and unhealthy specimens of other tendril bearing plants, similar rudiments 432 00:27:47.359 --> 00:27:51.240 may occasionally be observed in the bean. These filaments are 433 00:27:51.319 --> 00:27:54.240 variable in shape, as is so frequently the case with 434 00:27:54.359 --> 00:27:58.480 rudimentary organs. They are either cylindrical or fallaceous, or are 435 00:27:58.519 --> 00:28:02.039 deeply furrowed on the upper so they have not retained 436 00:28:02.079 --> 00:28:05.759 any vestige of the power of revolving. It is curious 437 00:28:05.799 --> 00:28:09.079 fact that many of these filaments, when fallaceous, have on 438 00:28:09.160 --> 00:28:13.440 their lower surfaces dark colored glands led those on the stipules, 439 00:28:13.640 --> 00:28:16.960 which excrete a sweet fluid, so that these rudiments have 440 00:28:17.039 --> 00:28:22.680 been feebly utilized. One other analogous case, though hypothetical, is 441 00:28:22.720 --> 00:28:27.359 worth giving. Nearly all the species of Lathyrus possess tendrils, 442 00:28:27.640 --> 00:28:31.839 but l. Nissolea is destitute of them. This plant has 443 00:28:31.920 --> 00:28:35.279 leaves which must have struck everyone with surprise who has 444 00:28:35.440 --> 00:28:38.440 noticed them, for they are quite unlike those of all 445 00:28:38.519 --> 00:28:44.039 common papillonaceaus plants, and resemble those of a grass. In 446 00:28:44.119 --> 00:28:48.640 other species l Africa, the tendril, which is not highly developed, 447 00:28:48.720 --> 00:28:52.160 for it is unbranched and has no spontaneous revolving power, 448 00:28:52.640 --> 00:28:56.000 replaces the leaves, the latter being replaced in function by 449 00:28:56.079 --> 00:28:59.559 large stipules. Now, if we suppose the tendrils of el 450 00:28:59.640 --> 00:29:03.559 Paca to become flattened and fallacious like the little rudimentary 451 00:29:03.640 --> 00:29:06.599 tendrils of the bean, and the large stipules to become 452 00:29:06.720 --> 00:29:09.799 at the same time reduced in size from not being 453 00:29:09.839 --> 00:29:14.680 any longer wanted, we should have the exact counterpart of L. Missolia, 454 00:29:15.079 --> 00:29:18.720 and its curious leaves are at once rendered intelligible to us. 455 00:29:18.920 --> 00:29:21.400 It may be added, as serving to sum up the 456 00:29:21.480 --> 00:29:24.839 foregoing views on the origin of tendril bearing plants, that 457 00:29:25.039 --> 00:29:29.240 Lnssolia is probably descended from a plant which was primordially 458 00:29:29.319 --> 00:29:32.799 a twiner. This then became a leaf climber, and the 459 00:29:32.880 --> 00:29:37.720 les afterwards converted by degrees into tendrils, with the stipules 460 00:29:37.759 --> 00:29:42.279 greatly increased in size through the law of compensation. After 461 00:29:42.319 --> 00:29:45.240 a time, the tendrils lost their branches and became simple. 462 00:29:45.759 --> 00:29:48.599 They then lost their revolving power, in which state they 463 00:29:48.640 --> 00:29:51.720 would have resembled the tendrils of the existing el faca, 464 00:29:52.200 --> 00:29:56.519 and afterwards losing their prehensile power and becoming fallacious, would 465 00:29:56.599 --> 00:30:00.279 no longer be thus designated. In this last stage that 466 00:30:00.319 --> 00:30:04.279 of the existing L. Nissoleia, the former tendrils would reassume 467 00:30:04.359 --> 00:30:07.720 the original function of leaves, and the stipules, which were 468 00:30:07.799 --> 00:30:12.599 recently much developed, being no longer wanted, would decrease in size. 469 00:30:12.680 --> 00:30:15.559 If species become modified in the course of ages, as 470 00:30:15.599 --> 00:30:20.319 almost all naturalists now admit, we may conclude that Lnisolia 471 00:30:20.440 --> 00:30:23.240 has passed through a series of changes in some degree 472 00:30:23.599 --> 00:30:27.839 like those here indicated. The most interesting point in the 473 00:30:27.960 --> 00:30:31.160 natural history of climbing plants is the various kinds of 474 00:30:31.240 --> 00:30:34.799 movements which they display in manifest relation to their wants. 475 00:30:35.319 --> 00:30:40.200 The most different organs, stems, branches, flower, peduncles, petioles, mid 476 00:30:40.279 --> 00:30:44.079 ribs of the leaves and leaflets, and apparently aerial roots 477 00:30:44.119 --> 00:30:47.920 all possess this power. The first action of a tendril 478 00:30:48.000 --> 00:30:51.359 is to place itself in a proper position. For instance, 479 00:30:51.440 --> 00:30:55.440 the tendril of the Kobea first rises vertically up, with 480 00:30:55.519 --> 00:30:58.960 its branches divergent and with the terminal hooks turned outwards. 481 00:30:59.559 --> 00:31:01.920 The young shoot at the extremity of the stem is 482 00:31:01.960 --> 00:31:04.920 at the same time bend to one side so

as 483 00:31:04.960 --> 00:31:08.039 to be out of the way. The young leaves of Chromatis, 484 00:31:08.160 --> 00:31:11.359 on the other hand, prepare for action by temporarily curving 485 00:31:11.359 --> 00:31:16.319 itself downwards so as to serve as grapnels. Secondly, if 486 00:31:16.319 --> 00:31:19.599 the twining plant or tendril gets by any accident into 487 00:31:19.599 --> 00:31:24.119 an inclined position, it soon bends upwards, though secluded from 488 00:31:24.200 --> 00:31:27.680 the light. The guiding stimulus, no doubt is the attraction 489 00:31:27.720 --> 00:31:30.480 of gravity. As Andrew Knite showed to be the case 490 00:31:30.519 --> 00:31:34.400 with germinating plants. If a shoot of any ordinary plant 491 00:31:34.440 --> 00:31:36.839 be placed in an inclined position in a glass of 492 00:31:36.920 --> 00:31:39.720 water in the dark, the extremity will in a few 493 00:31:39.759 --> 00:31:43.200 hours bend upwards, and if the position of the chute 494 00:31:43.279 --> 00:31:47.720 be then reversed, the downward chote reverses its curvature. But 495 00:31:47.799 --> 00:31:50.720 if the stolen of a strawberry, which has no tendency 496 00:31:50.720 --> 00:31:53.839 to grow upwards, be thus treated, it will curve downwards 497 00:31:53.839 --> 00:31:56.759 in the direction of instead of in opposition to the 498 00:31:56.839 --> 00:32:01.000 force of gravity, as with the very so it is 499 00:32:01.200 --> 00:32:05.200 generally with the twining shoots of the Hibertia dentata, which 500 00:32:05.240 --> 00:32:08.599 climbs laterally from bush to bush. For these shoots, if 501 00:32:08.640 --> 00:32:12.279 placed in positioning climbed downwards, show little and sometimes no 502 00:32:12.359 --> 00:32:17.000 tendency to curve upwards. Thirdly, climbing plants, like other plants, 503 00:32:17.039 --> 00:32:20.039 bend towards the light by a movement mostly analogous to 504 00:32:20.079 --> 00:32:23.880 the incurvation which causes them to revolve, so that their 505 00:32:23.880 --> 00:32:27.799 revolving movement is often accelerated or retarded in traveling to 506 00:32:27.960 --> 00:32:30.559 or from the light. On the other hand, in a 507 00:32:30.599 --> 00:32:35.400 few instances, tendrils bend towards the dark. Fourthly, we have 508 00:32:35.440 --> 00:32:39.839 the spontaneous revolving movement, which is independent of any outward stimulus, 509 00:32:40.079 --> 00:32:42.400 but is contingent on the youth of the part and 510 00:32:42.480 --> 00:32:45.759 on vigorous health. And this again, of course, depends on 511 00:32:45.799 --> 00:32:51.400 a proper temperature and other favorable conditions of light. Fifthly, tendrils, 512 00:32:51.519 --> 00:32:54.559 whatever their homological nature may be, and the petioles or 513 00:32:54.640 --> 00:32:58.880 tips of the leaves of leaf climbers, and apparently certain roots, 514 00:32:58.920 --> 00:33:02.400 all have the power of movement when touched and bend 515 00:33:02.480 -->

00:33:07.680 quickly towards the touched side. Extremely light pressure often suffices. 516 00:33:08.279 --> 00:33:10.680 If the pressure be not permanent, The part in question 517 00:33:10.799 --> 00:33:15.759 straightens itself and is again ready to bend on being touched. Sixthly, 518 00:33:15.799 --> 00:33:19.359 and lastly, tendrils, soon after clasping the support, but not 519 00:33:19.559 --> 00:33:23.400 after a mere temporary curvature, contract spirally. If they have 520 00:33:23.519 --> 00:33:26.680 not come into contact with any objects. They ultimately contract 521 00:33:26.720 --> 00:33:30.359 spirally after ceasing to evolve, but in this case the 522 00:33:30.400 --> 00:33:33.839 movement is useless and occurs only after a considerable lapse 523 00:33:33.839 --> 00:33:37.000 of time. With respect to the means by which these 524 00:33:37.079 --> 00:33:40.079 various movements are affected, there can be little doubt from 525 00:33:40.079 --> 00:33:43.319 the researches of Sax and h debrees that they are 526 00:33:43.480 --> 00:33:47.960 due to unequal growth, but from the reasons already assigned, 527 00:33:48.000 --> 00:33:51.519 I cannot believe that this explanation applies to the rapid 528 00:33:51.559 --> 00:33:56.039 movements from a delicate touch. Finally, climbing plants are sufficiently 529 00:33:56.160 --> 00:33:59.559 numerous to form a conspicuous feature in the vegetable kingdom, 530 00:34:00.160 --> 00:34:05.240 especially in tropical forests America, which so abounds with arboreal animals, 531 00:34:05.279 --> 00:34:08.960 as mister Bates remarks, likewise abounds, according to Mole and 532 00:34:09.039 --> 00:34:12.360 Palm with climbing plants, and of the tendril bearing plants 533 00:34:12.400 --> 00:34:15.760 examined by me, the highest developed kinds are natives of 534 00:34:15.800 --> 00:34:22.079 this grand continent, namely the several species of Bignonia, achromocarpus, Cobea, 535 00:34:22.519 --> 00:34:26.639 and Empelopsis. But even in the thickets of our temperate regions, 536 00:34:26.639 --> 00:34:30.039 the number of climbing species and individuals is considerable, as 537 00:34:30.079 --> 00:34:32.840 will be found by counting them. They belong to so 538 00:34:32.960 --> 00:34:36.679 many and wildly different orders. To gain some rude idea 539 00:34:36.719 --> 00:34:39.639 of their distribution in the vegetable series, I marked for 540 00:34:39.760 --> 00:34:42.760 the lists given by Mole and Palm, adding a few. 541 00:34:42.840 --> 00:34:46.199 Myself and a competent botanist, no doubt could have added 542 00:34:46.199 --> 00:34:50.559 many more all those families in Lindley's Vegetable Kingdom which 543 00:34:50.559 --> 00:34:56.320 include twiners, leaf climbers, or tender bearers. Lindley divides phenerogamic 544 00:34:56.400 --> 00:35:00.199 plants into fifty nine alliances. Of these, no legs less 545 00:35:00.239 --> 00:35:03.360 than thirty five include climbing plants of the above kinds, 546 00:35:03.639 --> 00:35:07.480 hook and root climbers being excluded. To these, A few 547 00:35:07.599 --> 00:35:11.679 cryptogamic plants must be added. When we reflect on the 548 00:35:11.679 --> 00:35:14.599 wide separation of these plants in the series, and when 549 00:35:14.599 --> 00:35:16.719 we know that in some of the largest and well 550 00:35:16.719 --> 00:35:23.320 defined orders, such as the Compositae Rubasia, Scropophilariae, cia, the Lasia, 551 00:35:23.519 --> 00:35:27.320 et cetera, species in only two or three genera have 552 00:35:27.400 --> 00:35:30.760 the power of climbing, the conclusion is forced on our 553 00:35:30.800 --> 00:35:34.599 minds that the capacity of revolving on which most climbers depend, 554 00:35:34.880 --> 00:35:38.239 is inherent, though undeveloped, in almost every plant in the 555 00:35:38.320 --> 00:35:42.800 Vegetable Kingdom. It has often been vaguely asserted that plants 556 00:35:42.840 --> 00:35:46.159 are distinguished from animals by not having the power of movement. 557 00:35:46.760 --> 00:35:49.440 It should rather be said that plants acquire and display 558 00:35:49.480 --> 00:35:52.559 this power only when it is of some advantage to them, 559 00:35:52.920 --> 00:35:55.840 and this being of comparatively rare occurrence. As they are 560 00:35:55.840 --> 00:35:57.960 fixed to the ground and food is brought to them 561 00:35:58.079 --> 00:36:01.199 by the air and rain. We see how high in 562 00:36:01.239 --> 00:36:04.119 the scale of organization a plant may rise. When we 563 00:36:04.159 --> 00:36:07.159 look at one of the more perfect tendril bearers, it 564 00:36:07.239 --> 00:36:10.840 first places its tendrils ready for action, as a polypus 565 00:36:10.880 --> 00:36:14.480 places its tentacula. If the tendril be displaced, it is 566 00:36:14.559 --> 00:36:17.400 acted on by the force of gravity and rights itself. 567 00:36:17.800 --> 00:36:20.199 It is acted on by the light and bends towards 568 00:36:20.280 --> 00:36:23.079 or from it, or disregards it, whichever may be the 569 00:36:23.119 --> 00:36:27.599 most advantageous. During several days, the tendrils or internodes or 570 00:36:27.679 --> 00:36:32.519 both spontaneously revolve with a steady motion. The tendril strikes 571 00:36:32.519 --> 00:36:35.760 some object and quickly curls round and firmly grasps it. 572 00:36:36.519 --> 00:36:39.320 In the course of some hours it contracts into a spire, 573 00:36:39.679 --> 00:36:44.440 dragging up the sidam and forming an excellent spring. All 574 00:36:44.480 --> 00:36:48.440 movements now cease. By growth, the tissue soon become wonderfully 575 00:36:48.480 --> 00:36:51.760 strong and durable. The tendril has done its work, and 576 00:36:51.880 --> 00:36:57.639 has done it in an admirable manner. End of Chapter five. 577 00:36:58.679 --> 00:37:01.920 End of the Movement and Habits of Climbing Plants by 578 00:37:02.000 --> 00:37:02.880 Charles Darwin,