CLIMBING PLANTS. 



709 



The erect stems of the Ivy, adorned with cordate shining foliage-leaves when 

 treated as slips or cuttings, send absorbent roots into the ground and ramify; 

 but, strangely enough, the shoots wliich they develop, although they now spring 

 close upon the ground, do not become climbing stems, but exhibit exactly the 

 same structure, the same erect position, and the same foliage as the shoots on 

 the top of a wall or on the summit of a tree. Anyone seeing for the first time 



Fig. 170. — Bignonia argyro-violacea, from tiu' Ikiiiivs hi ilie Kio Negro in Brazil. 



such Ivy grown in pots, is tempted to mistake it for some erect tropical Aredia, 

 and even experienced gardeners and botanists may be misled by these plants. 

 We are involuntarily i-eminded by these successive shoot-structures, which difi'er 

 so much in their outer form and internal constniction, of the alternation of 

 generations occurring in Vascular Ci'yptogams, and so much the more since the 

 climbing shoots which precede the erect flowering shoots do not develop flowers 

 and fruits, and thus to some extent resemble an asexual generation. 



Several Indian species of fig, the stems of which climb up rocky walls and 



