200 CONCLUDING EEMAEKS. Chap. V. 



the habit of climbing. In the cases given of certain 

 South African plants belonging to great twining fami- 

 lies, which in their native country never twine, but 

 reassume this habit when cultivated in England, we 

 have a case in point. In the leaf-climbing Clematis 

 flammula, and in the tendril-bearing Vine, we see no 

 loss in the power of climbing, but only a remnant of the 

 revolving power which is indispensable to all twiners, 

 and is so common as well as so advantageous to most 

 climbers. In Tecoma radicans, one of the Bignoniaceae, 

 we see a last- and doubtful trace of the power of 

 revolving. 



With respect to the abortion of tendrils, certain 

 cultivated varieties of Cueurbita pepo have, according 

 to Naudin,* either quite lost these organs or bear 

 semi-monstrous representatives of them. In my 

 limited experience, I have met with only one ap- 

 parent instance of their natural suppression, namely, 

 in the common bean. All the other species of Vida, 

 I believe, bear tendrils ; but the bean is stiff enough 

 to support its own stem, and in this species, at the 

 end of the petiole, where, according to analogy, a ten- 

 dril ought to have existed, a small pointed filament 

 projects, about a third of an inch in length, and which 

 is probably the rudiment of a tendril. This may be 

 the more safely inferred, as in young and unhealthy 

 specimens of other tendril-bearing plants similar rudi- 

 ments may occasionally be observed. In the bean 



♦ Annales des Sc. Nat. 4th series, Bot. torn. vi. 1856, p. 31. 



