VII.] PISTIL. 91 



19. The Pistil. — When in our first chapter we spoke of 

 all the organs borne by the stem as leaves of some kind, you 

 were not in so favourable a position, as from subsequent 

 experience you must now be, to appreciate the broad sense 

 in which the word leaf was employed. I repeat, all the 

 organs borne by the stem and its branches are modifications 

 of one leaf-type. By this statement you are not to under- 

 stand that a petal, or a stamen, or a carpel, is a modified 

 foliage-leaf, any more than that a foliage-leaf is any one of 

 these organs modified ; but they are all alike modifications 

 of one common leaf-type which has only an ideal existence. 

 Thus the leaf may be an organ either for the purpose of 

 nutrition or of reproduction, or it may be merely a pro- 

 tective organ ; but whatever function it is designed to fulfil — 

 in other words, whatever special organ it becomes — it is 

 modified appropriately to the function which it has to perform. 

 Thus we have the nutritive leaves, broad, green expansions, 

 exposing the fluids of the plant to the influence of light ; 

 the protective leaves, hard and scale-like, as the scale-leaves 

 of leaf-buds; or more delicate, and often showy and coloured, 

 as the enveloping leaves of the flower. 



The essential reproductive leaves invariably assume one 

 of two forms — either that of the staminal leaf, with the blade 

 (the anther) thickened and its tissue partially transformed 

 into pollen, or that of the carpellary leaf, which is hollow, 

 bearing a seed-bud or seed-buds (ovules) upon its margin 

 inside, and terminating above in a stigma. 



That this is a correct view to take of the nature of the 

 leafy organs of a plant we have incontestable external 

 evidence to prove. And this evidence is principally of 

 two kinds. Either we find one form of leaf passing by 

 insensible gradations into another, as foliage-leaves into 

 sepals, sepals into petals, petals into stamens, or we find 



