124 FLOWER OF THE HIGHER SEED PLANTS 



A whorl of stamens is frequently suppressed, so that only one 

 circle is present in the flower (Fig. 128). 



Multiplication of whorls is particularly frequent among the 

 stamens, but other whorls may also show it (see Figs. 149, 150). 



FIG. 123. Flower of 

 (European) wild 

 ginger, with calyx 

 but no petals 



After Wossidlo 



A B 



FIG. 124. Flowers of willow 



A, stamina te flower; B, pistil- 

 late flower. Magnified. After 

 Decaisue 



149. Unisexual flowers. The stamens 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. 124) each flower of the catkin (Fig. 143) consists 

 merely of a pistil or a group of (usually two) stamens springing 



from the axil of a small bract. 



Staminate and pistillate flowers may be 

 borne on different plants, as they are in 

 the willow, or they may be borne on the 

 same plant, as in the hickory and the hazel 

 among trees, or in the castor-oil plant, 

 Indian corn, and the begonias. When stam- 

 inate and pistillate flowers are borne on 

 FIG. 125. Bilaterally separate plants, such a plant is said to be 



dioecious, that is of two households ; when 

 or pansy 



both kinds of flower appear on the same 

 individual, the plant is said to be monoecious, that is of one 

 household. 



