34. THE FERTILISATION OF FLOWERS. [cuap. 
stamens and pistil are the essential organs, because 
they are necessary for the produc- 
tion of seeds. — The sales 
usually green; the corolla gene- 
rally conspicuous from its bright 
colours. In some plants the 
calyx or the corolla is entirely 
wanting, in which case the floral 
covering is termed a ferzanth, as 
in the Crocus and Lily. 
The stamens consist of two parts, the filament or 
stalk (F), and the auther or pollen-case (An). The an- 
ther is the principal part of the organ, and 
is filled with a very fine powder like flour. 
When the anther is ripe, it splits open, 
and sets free this powder, or pollen as it is 
called. Examined under the microscope, 
this pollen is seen to consist of very 
minute cells filled with protoplasm (fig. 
-40). The fzstz/ occupies the centre of the 
flower, and is surrounded by the stamens 
when these are present. It consists of 
three parts—the stzgma or surface, the 
style or stalk, and the ovavy at its base, 
The ovary contains the immature seeds or ovules, 
which require to be fertilised by the contents of a 
pollen grain before they can grow into perfect seeds. 
The style may be absent, and the stigma placed 
directly on the ovary. The stigma is either sticky, 
rough, or covered with long hairs, to retain the pollen 
grains. In some plants the stamens are found in one 
flower and the pistil in another; they are then termed 
Fic. 38. 
Fic. 39. 
