63 a 



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 f ; had the right side 



Fig. 370,— Leaf of Oxalis caynea, i diurnal, 2 nocturnal position. 



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 



Fig. 371.— Transverse section of tlie motile organ of a leaBet of Oxalis carnea. 



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: 



