142 TENDRIL-BEARERS. Cuae. IV. 
which corresponds with the sub-peduncle one single 
flower-bud! Hence there can be no doubt that the 
tendril is a modified flower-peduncle. 
Another kind of gradation well deserves notice. 
Flower-tendrils (B, fig. 10) sometimes produce a few 
flower-buds. For instance, on a vine growing against 
my house, there were thirteen and twenty-two flower- 
buds respectively on two flower-tendrils, which still 
retained their characteristic qualities of sensitiveness 
and spontaneous movement, but in a somewhat lessened 
degree. On vines in hothouses, so many flowers are 
occasionally produced on the flower-tendrils that a 
double bunch of grapes is the result ; and this is techni- 
cally called by gardeners a“ cluster.” In this state the 
whole bunch of flowers presents scarcely any resem- 
blance 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- 
stalks closely resemble in structure those borne by 
Cissus. This genus, belonging to the same family of 
the Vitaces, produces well-developed tendrils and 
ordinary bunches of flowers ; but there are no gradations 
between the two states. Ifthe genus Vets had been 
unknown, the boldest believer in the modification of 
species would never have surmised that the same 
individual plant, at the same period of growth, 
would have yielded every possible gradation between 
ordinary flower-stalks for the support of the flowers 
and fruit, and tendrils used exclusively for climbing. 
But the vine clearly gives us such a case; and it 
