REPRODUCTIVE ORGANS O¥ PLANTS. 29] 
The assimilation of carbon in the plant is most inti- 
mately connected with the chlorophyll, which has been no- 
ticed as the green coloring matter of the leaf, and depends 
also upon the solar rays. 
CHAPTER IV. 
REPRODUCTIVE ORGANS OF PLANTS. 
§ 1. 
THE FLOWER. 
The onward growth of the stem or of its branches is 
not necessarily limited, until from the terminal buds, in- 
stead of leaves, only FLowers unfold. When this happens, 
as is the case with most annual and biennial plants, raised 
on the farm or in the garden, the vegetative energy has usu- 
ally attained its fullest development, and the reproductive 
function begins to prepare for the death of the individual 
by providing seeds which shall perpetuate the species. 
There is often at first no apparent difference between 
the leaf-buds and flower-buds, but commonly in the later 
stages of their growth, the latter are to be readily dis- 
tinguished from the former by their greater size, and by 
peculiar shape or color. 
The Flower is a short branch, bearing a collection of 
organs, which, though usually having little resemblance 
to foliage, may be considered as leaves, more or less mod- 
ified in form, color, and office. 
The flower commonly presents four different sets of or- 
gans, viz, Calyx, Corolla, Stamens, and Pistils, and is 
then said to be complete, as in case of the apple, potato 
