THE FLOWER OF THE HIGHER SEED-PLANTS 149 
following one, and all the members of each whorl are alike 
(Fig. 98). 
176. Suppression and Multiplication of Whorls. — Any 
whorl or part of a whorl may be suppressed. If one set of 
parts of the perianth is lacking, this is 
assumed to be the corolla 
flower is said to be apetalous (Fig. 99). 
Multipheation of whorls is particu- 
larly frequent among the stamens, but 
other whorls may also show it (see 
Figs. 117, 118). 
177. Unisexual Flowers. — The sta- 
mens and pistils may be produced in 
separate flowers, which are uniserual 
and the 
Fic. 99. Apetalous 
Flower of (European) 
Wild Ginger. 
(often called imperfect) flowers. In 
the very simple unisexual flowers of the willow (Fig. 100) 
each flower of the catkin (Appendix, Fig. 6) consists merely 
of a pistil or a group of (usually two) stamens springing 
Fic. 100. Flowers of Willow. 
(Magnified.) 
A, staminate flower; BP, pistillate 
flower. 
from the axil of a small bract. 
Staminate and pistillate 
flowers may be borne on dif- 
ferent plants, as they are in 
the willow, or they may be 
borne on the same plant, as 
in the castor-oil plant, Indian 
corn, and the begonias. When 
staminate and pistillate flow- 
ers are borne on 
plants, such a plant is said 
separate 
to be diwetous (of two house- 
holds); when both kinds of 
flower appear on the same individual, the plant is said to 
be monecious (of one household). 
