632 



LECTURE XXXVI. 



convex on the outside. This kind of tension is still more clearly shown in C, 

 where only the one side of the swelling tissue is separated from the strand, and 

 the latter now becomes itself curved by the extension of s ; had the right side 



^rG. 370.— Leaf of Oxalis 



diurnal, 2 nocturnal positii 



of the parenchyma not been cut away from C, but had it instead lost only a part 

 of its turgescence, then also the organ would have been compelled to make a 

 similar curvature to that in C. With the longitudinal tension thus shown, the 



S^CÄ 



Fig. 371.— Transverse section of the motile organ of a leaflet oi OxaHs i 



corresponding ' transverse tension also is connected, as is obvious at once from 

 D and E. Z> is a transverse plate of the organ, and in E it has been 

 divided into two halves by a longitudinal section: it is noticed in F how the 



