CLIMBING PLANTS. 



693 



aceae in great vai-iety. Sometimes the whole leaf-blade is metamorphosed into a 

 single tendril, as in the Yellow Vetchling {Lathyrus Aphaca); but usually tendrils 

 are formed only in the place of the terminal leaflet and of the upper leaflets of the 

 pinnate leaves, as may be seen especially in vetches, peas, and lentils ( Vicia, Pisum, 

 Ervum). It should be mentioned here that in proportion as the green tissue of the 

 leaf-blade is reduced in consequence of the formation of tendrils, the amount of 



Fig. 164. — Branch-tendrils of Serjania grarnatophora. 



green tissue of the lowest leaflets, leaf -stalks, and stipules increases; in other words, 

 that when tendrils appear in place of the upper leaflets, the lowest pair of leaflets 

 and the stipules form large green laminae. In many vetches even the stem and 

 leaf -stalks are beset with green leaf-like bands and wings. 



By a stem-tendril {cirrhus capreolus) is meant one which can be interpreted as 

 a stem-structure, and a distinction is drawn particularly between branch-tendrils 

 (cirrhus rameaneus) and floiver-stalk tendrils (cirrhus peduncularis) according as 

 to whether the tendril is to be regarded as a metamorphosed flower-bearing or 



