430 



GENERAL BOTANY 



Reproduction. In Sagittaria (Fig. 275) the flowers are borne 

 in clusters of three on the inflorescence axis, while in Pontederia 

 (Fig. 276) they occur in spikes. Cross-pollination is provided 

 for in Sagittaria, since plants are either moncecious or dioecious. 



FIG. 277. A field of sugar cane at Vera Cruz 

 After Freeman and Chandler 



In Pontederia the flowers are trimorphic, with three lengths 

 of stamens and pistils, which also insures cross-pollination. 



G-RAMINEAE (GRASSES AND SEDGES) 



FORAGE AND FOOD PLANTS 



Habitat and habit. The members of this family, including the 

 common grasses, bamboo, sugar cane, and cereal grains, are among 

 the most important and widely spread of all the monocotyledons. 

 The grasses proper are social plants, forming vast associations 



