146 



TENDKIL-BEAREUS. 



Chap. 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 cajpreolata. 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. 

 Tot. Soc. Edinburgh, vol xi. p. 

 2!)2) that the tendrils of Amp. 

 Veil chit bear small globubr discs 

 before ihey 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 



adhere to any surface. The ten- 

 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 Bignoniaccse. 



