82 ME. DAKWIX OX CLIMBING PLAXTS. 



come considerably elongated and had completely wound round 

 sticks, exactly like true tendrils. The whole length of another sub- 

 peduncle bearing only eleven flower-buds quickly became curved 

 when slightly rubbed; but even this scanty number of flowers 



rendered the stalk less sensitive than the other branch, that is, the 



flower-tendril ; for the latter after a lighter rub became curved in 

 a greater degree and more quickly than the sub-peduncle with its 

 few flowers. I have seen a sub-peduncle thickly covered with 

 flower-buds, but with one of the higher lateral branchlets bearing 

 from some cause only two buds, and this one branchlet had become 

 much elongated and had spontaneously caught hold of an ad- 

 joining twig ; in fact, it formed a little tendril. The increase of 

 length in the sub-peduncle (C) with the decreasing number of 

 its flower-buds is a good instance of the law of compensation. 

 Hence it is that the whole ordinary tendril is longer than the whole 

 flower-peduncle; thus, on one and the same plant, the longest 



(measured 



1) 



longest tendril was nearly double this length, namely 16 inches. 



The gradation from the ordinary state of the flower-peduncle, 

 as represented in the drawing (fig. 10), to that of the true tendril 

 (fig. 9) is perfect. We have seen that the sub-peduncle (C), whilst 

 still bearing from thirty to forty floAver-buds, may become some- 

 what elongated and partially assume all the characters of the 

 corresponding branch of the true tendril. Erom this state we can 

 trace every stage till we come to a full-sized common tendril, 

 bearing on the branch which corresponds with the sub-peduncle 

 one single flower-bud ! Hence there can be no doubt that the 

 tendi-il is a modified flower-peduncle. 



Another kind of gradation Avell deserves notice. The flower- 

 tendril (B, fig. 10) sometimes produces a few flower-buds; I 

 found thirteen and twenty-t^Ao on two flower-tendrils on a vine 

 growing against my house ; in this state they retain their charac- 

 teristic qualities of sensitiveness and spontaneous movement, but 

 in a somewhat lessened degree. On v-ines in hothouses, so many 

 flowers are occasionally produced by the flower-tendrils that a 

 double bunch of grapes is the result ; and this is technically called 

 by gardeners a "cluster." In this state the whole bunch of 



+ 



flowers presents scarcely any resemblance to a tendril; and, 

 judging from the facts already given, it would probably possess 

 little power of clasping a support, or of spontaneous movement. 

 Such flower-peduncles closely resemble in structure those borne 



