[Chap. LI SOME FAMILIES OF FLOWERING PLANTS 



697 



are present. The flowers may have three stamens and a pistil, or the 

 stamens and pistils may occur in different flowers. The fruit of the 

 grasses is a grain. 



Closely related and often confused with the grasses are the sedges, 

 Cyperaceae (Fig. 335), and rushes, Jiincaceae. The leaves of sedges are 



Fig. 335. A large sedge (Carex macrocephala) used to stabilize wind-blown 

 sand. The plant propagates vegetatively from rhizomes a foot or more below the 

 soil surface. Comtesy U. S. Soil Conservation Service. 



three-ranked on usually solid stems, as contrasted with the two-ranked 

 leaves and hollow stems of grasses. The flowers of rushes have a six- 

 parted green perianth. The fruit of a sedge is an akene; that of a rush, 

 a capsule. 



The palm family ( Palmaceae ) . Conspicuous plants of both the tropics 

 and the subtropics are the palms (Fig. 336). Because of their striking 

 appearance, they have been termed "the princes of the vegetable king- 

 dom. " Fossil remains indicate that at one time these plants were widely 

 distributed, even beyond the arctic circle. The two chief centers of 

 distribution of modern palms are tropical America and tropical Asia, 

 with a lesser third center in tropical Africa. The present distribution 

 of wild species of palms in the United States is limited to the south- 



