196 COSOLUDING EEMAEKS. Chap. Y. 



genus Mikania, there are leaf-climbing and twining 

 species. The leaf-climbing species of Clematis are 

 very closely allied to the tendril-bearing Naravelia. 

 The Fumariacese include closely allied genera which are 

 leaf-climbers and tendrU-bearers. Lastly, a species of 

 Bigrionia is at the same time both a leaf-climber and 

 a tendril-bearer; and other closely allied species are 

 twiners. 



Tendrils of another kind consist of modified flower- 

 peduncles. In this case we likewise have many in- 

 teresting transitional states. The common Vine (not 

 to mention the Cardiospermum) gives us every possible 

 gradation between a perfectly developed tendril and a 

 flower-peduncle covered with flowers, yet furnished with 

 a branch, forming the flower-tendril. When the latter 

 itself bears a few flowers, as we know sometimes is 

 the case, and still retains the power of clasping a 

 support, we see an early condition of all those tendrils 

 which have been formed by the modification of flower- 

 peduncles. 



According to Mohl and others, some tendrils consist 

 of modified branches : I have not observed any such 

 cases, and know nothing of their transitional states, 

 but these have been fully described by Fritz MuUer. 

 The genus Lophospermum also shows us how such a 

 transition is possible; for its branches spontaneously 

 revolve and are sensitive to contact. Hence, if the 

 leaves on some of the branches of the Lophospermum 

 were to abort, these branches would be converted 

 into true tendrils. Nor is there anything improbable 



