THE DIFFERENT FLOWERS. 195 
sure that this latter classification is a practicable one, 
but it is certainly well to place the English forcing va- 
rieties in a group alone. 
Pollination —Ill-shaped fruits.— Cucumbers are mo- 
neecious plants: that is, the sexes are borne in separate 
ffowers on the same plant. Fig. 67 represents the two 
kinds of flowers on the common field cucumber. P is 
the pistillate or fruit-bearing flower. The young cucum- 
ber, or ovary, can be seen below the petals or leaves 
of the flower. S shows the staminate flower, which per- 
sists only long enough to supply pollen to fertilize the 
pistillate flowers. The staminate flowers are more nu- 
merous than the pistillate, and they begin to appear 
67. The pollen-bearing and fruit-bearing flowers. 
earlier; a sufficient supply of pollen is therefore insured 
against all exigencies of weather or other untoward cir- 
cumstances. Out of doors the pollen is carried from 
the staminate to the pistillate flower by insects, but pol- 
len-carrying insects are absent from the greenhouse. If 
the flowers are fertilized in the house, therefore, the pol- 
len must be carried by hand. It is certain that some 
plants of English cucumbers will set fruit to perfection 
without seeds and entirely without the aid of pollen, 
but other plants (and in our experience they have been 
greatly in the majority) utterly refuse to do so. I do 
I4 FORC. 
