70 MR, DARWIN OX CLIMBING PLANTS, 



a certain extent, by the movement from tlie liglit or towards any 

 dark object ; for neither the intemodes nor the tendrils have any 

 proper revolving movement. From this latter circumstance, from 

 the slow movements of the tendrils after contact (though their 

 sensitiveness is retained for an unusual length of time), from their 

 simple structure and shortness, this plant shows less perfection 

 in its means of climbing than any other tendril-bearing plant 

 observed by me. Wliilst young and only a few inches in height, 

 it does not produce any tendrils ; and considering that it grows 

 to only about 8 feet high, that the stem is zigzag, and is furnished, 

 as well as the petioles, with spines, it is surprising that it should 

 be provided with tendrils, comparatively inefficient though they 

 be. The plant might have been left, one would have thought, 

 to climb by the aid of its spines alone, like our brambles. But, 

 then, it belongs to a genus some of the species of which are fur- 

 nished with much longer tendrils ; and we may believe that S. 

 aspera is endowed with these organs solely from being descended 

 from progenitors more highly organized in this respect. 



FuMABTACEiE. — Covt/dalis clavicidata, — According to Mohl 

 (S. 43), both the leaves and the extremities of the branches 

 are converted into tendrils. In the specimens examined by 

 me all the tendrils were certainly foliar, and it is hardly credible 

 that the same plant should produce tendrils of such widely dif- 

 ferent homological natures. Nevertheless, from this statement 

 by Mohl, I have ranked this Corydalis amongst tendril-bearers ; 

 if classed exclusively by its foliar tendrils, it would be doubtful 

 whether it ought not to have been placed amongst leaf-climbers, 

 with its allies, Fumaria and Adlumia. A large majority of its 

 so-called tendrils still bear leaflets, though excessively reduced in 

 size ; some few of them may be properly designated as tendrils, for 

 they are completely destitute of lamina? or blades. Consequently 

 we here behold a plant in an actual state of transition from a leaf- 

 climber to a tendril-bearer. Whilst the plant is young, only the 

 outer leaves, but when full-grown all the leaves, have their extre- 

 inities more or less perfectly converted into tendrils. I have 

 examined specimens from one locality alone, viz. Hampshire; and 

 it is not improhable that plants growing under different conditions 

 might have their leaves a little more or less changed into true 

 teudrlla. 



Wliilst the plant is quite young, the first-formed leaves are not 

 modified in any way, but those next formed have their terminal 

 leaflets reduced in size, and soon all the leaves assume the struc- 



