THE FLOWER 



87 



of tke presence or absence of the calyx and corolla. If either 

 stamens or pistils are absent, it is imperfect (diclinous). If the 

 stamens only are present, it is sta,minaie. If the pistils only are 

 present, it is pistillate. 



When both the staminate and pistillate flowers are on the 

 same plants, as in the corn and castor-oil plants, it is monoecious 

 (one household), but if on different plants, as in the willows and 



Fig. 67. — Legume blossom: (a) and (b) the blogsom; (c) the blossom dissected showing the 

 petals; (d) the sepal, stamen and pistil; (e) the mature seed pod. 



mulberries, it is dioecious (two households).. When some of the 

 flowers on an individual plant are perfect and others imperfect 

 it is polygamous. 



If the parts of the flower are attached below the ovary, the 

 ovary is superior; but if above, it is inferior. If each set or 

 circle of organs is free from the other circles, the flower is 

 hypogynous ; if the sepals, petals and stamen arise from an urn- 

 like structure surrounding and inserted below the pistil, the 

 flower is perigynous. If the urn is closed so that all the organs 

 appear to arise from the top of the ovary, the flower is epigynovs. 



