TEXDBIL-BEARERS. 103 



when the stem spirally ascends a thin upright stick, but they can 

 seize any twig or branch lying beneath them j but when the stem 

 spirally ascends a somewhat thicker stick, a slight degree of sensi- 

 tiveness in the petioles is brought into play, and thej r wind their 

 tendrils round the stick. In B. unguis and B. Tweedyana the sen- 

 sitiveness, as well as the power of movement, in the petioles is 

 greatly augmented ; and the tendrils and petioles are thus inex- 

 tricably wound together round thin upright sticks ; but the stem, 

 in consequence, does not twine so well : B. Tweedyana, in addition, 

 emits aerial roots which adhere to the stick. In B. venmta the 

 tendrils have lost the bird's-foot structure, and are converted into 

 long three-pronged grapnels ; these exhibit a conspicuous power of 

 spontaneous movement ; the petioles, however, have lost their 

 sensitiveness. The stem can spirally twine round an upright stick, 

 and is aided in its ascent by the tendrils alternately seizing the 

 slide some way above and then spirally contracting. In this and 

 all the following species the tendrils spirally contract after seizing 

 any object. In B. littoralis and B. Chamlcrlaynii the tendrils, which 

 have the same structure as in B. venusta, and the non-sensitive 

 petioles and the internodes all spontaneously revolve. The stem, 

 however, cannot spirally twine, but ascends an upright stick by 

 both tendrils, seizing it above. In B. littoralis the tips of the 

 tendrils become developed into adhesive disks. In B. speciosa and 

 B. picta we have similar powers of movement, but the plant cannot 

 spirally twine round a stick ; it can, however, ascend by clasping 

 it with one or both of its unbranched tendrils, on their own level ; 

 and these exhibit the strange, apparently useless, habit of con- 

 tinually inserting their pointed ends into minute crevices and 

 holes. In B. caprcolaia the stem twines in an imperfect manner ; 

 the much-branched tendrils revolve in a capricious manner, and 

 they have the power of bending in a conspicuous manner from 

 the light to the dark ; their hooked extremities, even whilst im- 

 mature, crawl into any crevice, or, when mature, seize any thin 

 projecting point ; in both cases they develope adhesive disks, 

 which have the power of enveloping by growth the finest fibres. 



In the allied Eccremocarpm the internodes, petioles, and ten- 

 drils all spontaneously revolve together ; its much-branched ten- 

 drils resemble those of Bignonia capreolata, but they do not turn 

 from the light ; and their bluntly hooked extremities, which arrange 

 themselves so neatly to any surface, do not form adhesive disks ; 

 they act best when ca'ch seizes a few thin stems, like the culms of 

 a grass, which they afterwards draw together by their spiral con- 



