STKUCTUEE OF THE FLOWER AND ITS ORGANS. 145 



petals have fallen and the seed has ripened. The receptacle 

 of the rose, Fig. 120, is hollow and the pistils arise from its 

 interior surface. 



178. Imperfect or Separated Flowers. — The stamens and 

 pistils may be produced in separate flowers, which are, of 

 course, imperfect. This term does not imply that such flowers 

 do their work any less perfectly than others, but only that 

 they have not both kinds of essential organs. 



In the very simple imperfect flowers of the 

 willow, Fig. 121, each flower of the catkin. 

 Fig. 108, 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 staminate and pis- 

 tillate flowers are borne on separate plants, 

 such a plant is said to be dioecious, that is, of-two-households ; 

 when both kinds of flower appear on the same individual, the 

 plant is said to be moruecious, that is, of-one-household. 



179. Study of Imperfect Flowers. — Examine, draw, and describe 

 tlie imperfect flowers of some of tlie following dioecious plants and one 

 of the monoecious plants i : 



Fig. 120.— a Hose, 

 Longitudinal Sec- 

 tion. 



Dioecious plants 



Monoecious plants 



early meadow rue, 



willow, 



poplar. 



walnut, oak, chestnut, 



hickory, alder, beech, 



birch, hazel, begonia. 



1 For figures and descriptions of these or allied flowers consult Gray's Manual of 

 Botany, Emerson's Trees and Shrubs of M(i^>iachusetts. Xewliall's Trees of the 

 Northern United States, or Le Maout and Decaisne's Traits General de Botanique. 



