146 TENDRIL-BEAEEES. 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 adhesiye 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 enTeloped, 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- 



liot. Soc. Edinburgh, vol zi. p. drils, therefore, of one species of 



292) that the tendrils of Amp. Ampelopais require the stimulus 



Veitchii bear small globular discs of contact for the first deyelopment 



before they have come into contact of their discs, whilst those of 



with any object ; and I have since another species do not need any 



observed the same fact. These such stimulus. We have seen an 



discs, however, increase greatly exactly parallel case with two 



in size, if they press against and species of BignoniaccsB. 



