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 which they develop, although they now spring 

 dose 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 the banks of the Rio Negro in Brazil. 



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

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

 We are involuntarily reminded by these successive shoot-structures, which diifer 

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

 generations occurring in Vascular Cryptogams, 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 



