194 



FORMATIONS AND GUILDS 



[Part II 



a support, curl round it. Morphologically the tendrils are either leaves or 

 axes. Oecologically they are very varied, so that, following H. Schenck, 



we may arrange tendril- 

 climbers, in the widest 

 sense, into six groups 

 according to their modes 

 of climbing : — 



In leaf- climbers a part, 

 petiole or blade, of the 

 otherwise unmodified leaf 

 is endowed with the ne- 

 cessary irritability. For 

 instance, Clematis Vi- 

 talba is a petiole-climber, 

 Fumaria officinalis in its 

 varieties Wirtgenii and 

 vulgaris a leaf- blade 

 climber ; Flagellaria in- 

 dica, a monocotyledon- 

 ous plant common in the 



Fig. 103. Securidaca Sellowiana, Klotzsch. Lateral shoot tropics of the Old World, 



acting as a tendril. Two-thirds of natural size. After H. . . . 



Schenck. is a leaf-tip climber. 



Fig. 104. Dalbergia variabilis, Yog. Old 

 and considerably thickened twining branch. 

 Two-thirds of natural size. After H. Schenck. 



Fig. 105. Strychnos triplinervia, Mart. Some- 

 what old lignified and thickened climbing 

 hooks. 



In leaf-tendril climbers, the leaf, or a part of it, is differentiated as a 

 filamentous organ functioning as a tendril only. We see this in the pea 

 and other Vicieae, Cucurbitaceae, and many other plants. 



