392 



ON THE VALVE OF CHARACTERS. 



a flower,are analogous to stipulse with regard to leaves, yet the former 

 are always sufFultient organs. The latter only so when abnormal de- 

 veloperaent takes place. Stipulae besides are always lateral with regard 

 to their leaves. 



Monopetalism is rare, although if it were a proof of imperfection, 

 it should be more frequent among Mono than Dicotyledons. Cohe- 

 sion between the ovary and calyx is much more frequent. 



Although monopetalism is rare, when considered relatively to 

 numbers of families, yet it is very common as to species, owing to 

 the bulk of many of the orders. There is however various sorts of 

 cohesion. 



Cohesion is more common, as might be expected, between similar, 

 than dissimilar organs. 



The most frequent is that between carpellary leaves. 



Mr. Brown's idea of the nature of stomata is borne out by the 

 modifications and functions of these organs in the pitchers of Ne- 

 perthes and Dischidia. 



