146 TENDRIL-BEARERS. Cuar. IV. 
their under-sides the well-known little discs or cushions 
with which they adhere firmly. In one case the tips 
were slightly swollen in 38 hrs. after coming into 
contact with a brick; in another case they were 
considerably swollen in 48 hrs., and in an additional 
24 hrs. were firmly attached to a smooth board; and 
lastly, the tips of a younger tendril not only swelled 
but became attached to a stuccoed wall in 42 hrs. 
These adhesive discs resemble, except in colour and 
in being larger, those of Bignonia capreolata. When 
they were developed in contact with a ball of tow, the 
fibres were separately enveloped, but not in so effective 
a manner as by B. capreolata. Discs are never de- 
veloped, as far as I have seen, without the stimulus of 
at least temporary contact with some object.* They 
are generally first formed on one side of the curved tip, 
the whole of which often becomes so much changed 
in appearance, that a line of the original green tissue 
can be traced only along the concave surface. When, 
however, a tendril has clasped a cylindrical stick, an 
irregular rim or disc is sometimes formed along the 
inner surface at some little distance from the curved 
* Dr. M’Nab remarks (Trans. adhere to any surface. The ten- 
Bot. Soc. Edinburgh, vol xi. p, 
292) that the tendrils of Amp. 
Veitchii bear small globular discs 
before they have come into contact 
with any object; and I have since 
observed the same fact. These 
discs, however, increase greatly 
in size, if they press against and 
drils, therefore, of one species of 
Ampelopsis require the stimulus 
of contact for the first development 
of their discs, whilst those of 
another species do not need any 
such stimulus. We have seen an 
exactly parallel case with two 
species of Bignoniacee. 
