VI.] 



FOKMS OF LEAF IN LATHY RUS. 



137 



is smaller in proportion than it would be in leaves of 

 the ordinary form. This is, I believe, the reason why 

 succulent leaves and stems are beneficial in very 

 dry climates, such as the Canaries, Cape of Good 

 Hope, &c. 



The genus Lathyrus, the wild pea, contains two 

 abnormal and interesting species in which the 

 foliaceous organs give the plant an appearance very 



Fig. IZ.—Lathyna niger. 



Fig. 89. — Lathyrus apkaca. 



unlike its congeners. Fig. 88 represents L. niger with 

 leaves of the ordinary type. In the yellow pea 

 {L. aphaca, Fig. 89), the general aspect is very 

 different, but it will be seen on a closer inspection 

 that the leaves are really absent, or, to speak more 

 correctly, are reduced to tendrils, while the stipules, 

 on the contrary, are, in compensation, considerably 

 enlarged. They must not, therefore, be compared 



