Coar. IV. SUMMARY. 177 
the stem twines round a somewhat thick stick, a slight 
degree of sensitiveness possessed by the petioles is 
brought into play, and the whole leaf together with 
the tendril winds round it. In B. wnguis the petioles 
are more sensitive, and have greater power of move- 
ment than those of the last species; they are able, 
together with the tendrils, to wind inextricably round 
a thin upright stick; but the stem does not twine 
so well. B. Tweedyana has similar powers, but in 
addition, emits aérial roots which adhere to the wood. 
In B. venusta the tendrils are converted into elongated 
three-pronged grapnels, which move spontaneously in 
a conspicuous manner; the petioles, however, have lost 
their sensitiveness. The stem of this species can twine 
round an upright stick, and is aided in its ascent by 
the tendrils seizing the stick alternately some way 
above and then contracting spirally. In B. littoralis 
the tendrils, petioles, and internodes, all revolve spon- 
taneously The stem, however, cannot twine, but ascends 
an upright stick by seizing it above with both tendrils 
together, which then contract into a spire. The tips 
of these tendrils become developed into adhesive discs. 
B. speciosa possesses similar powers of movement as 
the last species, but it cannot twine round a stick, 
though it can ascend by clasping the stick horizon- 
tally with one or both of its unbranched tendrils. 
These tendrils continually insert their pointed ends 
into minute crevices or holes, but as they are always 
withdrawn by the subsequent spiral contraction, the 
habit seems to us in our ignorance useless. Lastly, 
