TEtfDBILS OF VITIS GOKGTLODES. 309 



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possessed by any tendrils. We have seen that such disks are formed 

 by two species of Bignonia, by Ampelopsis, and, according to 

 Naudin, by the Cucurbitaceous genus Peponopsis adlicerens" By 

 this we observe that they are curiously found in widely distinct 

 natural orders, and are not by any means a generic peculiarity. 



I notice in the plant before us ( V. gongylodes) that, although 

 the disks are able, as I have seen, to attach themselves to a 

 nearly smooth surface, yet they still prefer a crevice in which to 

 insert themselves ; and the tendrils possess an extensive power 

 of search to find one. I have seen the case of a tendril with 

 three branches, each with its disk in the same crevice, where of 

 course they have the advantage of wedging themselves by an 

 accession of cellular tissue. The tendrils also delight to twine, or 

 clasp, and do not then always further develop their adhesive disks; 

 sometimes they do, however, and then, as it were, clench their at- 

 tachment. These tendrils having a well-developed revolving move- 

 ment, it is interesting to note that such is not always the case with 

 the disk-bearing tendrils of other plants. It does not happen with 

 Ampelopsis hederacea, and probably not with A. Veitchi, but again 

 occurs in Bignonia capreolata. The adhesive disks ofVitis gongylodes 

 apparently enlarge w r hen most necessary : in one case the arms of a 

 tendril had about half-encircled a thick round bar; and this being 

 an insufficient support, the disks grew to a large size, so that a 

 firm hold was obtained. The disks sometimes enlarge without 

 forming an attachment to an object ; but this perhaps happens 

 from previous irritation, as supposed in the case of Ampelopsis 

 hederacea by Mr. Darwin. In one case two tendrils had met 

 each other through an opening in ornamental ironwork ; and in 

 this position they became entwined together, and thus formed a 

 strong support to the branch, just as one might clasp the hands 

 over a bar and so cling to it. This I mention, bearing in mind 

 that when the tendrils of Bignonia dioica become entwined with 

 each other, they again release themselves. The power of clasping 

 or entwining a support is perfect; a bar 1| inch broad I have 

 seen well embraced. And in addition to this and the development 

 of adhesive disks, there is frequently a growth of whitish adhe- 

 sive tissue along the course of the entwining branch at points of 



of Hanbu 



firmly 



adh 



hesive cellular layer can be," a remark which applies to this and 



