THE FLOWER OF THE HIGHER SEED-PLANTS 149 



Fig. 



9. Apetalous 

 Flower of (European) 

 Wild Ginger. 



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 and the 

 flower is said to be apetalous (Fig. 99). 



]\lultiplication of whorls is particu- 

 larly frequent among the stamens, but 

 other whorls may also show it (see 

 Fi-s. 117, 118). 



177. Unisexual Flowers The sta- 

 mens and pistils may be produced in 

 separate flowers, which are unisexual 

 (often called imperfect) flowers. In the 

 very simple unisexual flowers of the willow (Fig. 100) each 

 flower of the catkin (Appendix I, Fig. 6) consists merely 

 of a pistil or a group of (usually iwo) stamens springing 



from the axil of a small bract. 

 Staminate and pistillate 

 flowers ma}' 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 separate 

 plants, such a plant is said 

 to be dkecious (of two house- 

 holds); when both kinds of 



flower appear on the same individual, the plant is said to 



be monoecious (of one household). 



Flowers of Willow. 

 (Magnified.) 



j4, staminate flower ; 5, pistillate 

 flower. 



