THE GRASSES 199 



probably in order that it may be advantaged by cross- 

 pollination. The Water-Plantains (Alisma) are also 

 conspicuous members of this group. 



But the most important of the Monocotyledons 

 are the Grasses, which are cosmopolitan, and include 

 species of great economic value. They supply food for 

 man and beast. The cereals wheat, barley, oats, rye, 

 rice, etc. which are of inestimable value as food for 

 man, are all grasses; the herbivorous ox eats grasses 

 and transforms them into beef; man eats the beef, and 

 in this respect is a vegetarian, and a grass-eater, once 

 removed. Wheat (Tridtum vulgar e), Rye (Secale 

 cereale), Barley (Hordeum vulgar e), Oats (Avena saliva), 

 and Maize (Zea mais) are widely cultivated in temperate 

 regions, the latter very largely in America. Rice 

 (Oryza sativa) is of the utmost importance in tropical 

 climes, and Millet (Andropogon Sorghum) is an exten- 

 sively cultivated African cereal. The Sugar-Cane (Sac- 

 charum afficinarum) is a perennial grass indigenous in 

 tropical Asia and cultivated, on account of its sugar- 

 yielding sap, throughout the tropics. The tropical 

 Bamboos (genus Bambusa) are also grasses, and, as every- 

 one knows, are useful in a hundred-and-one ways: 

 they serve as material for houses, bridges, ladders, 

 water-conducting pipes, and even cooking vessels. 

 Some of these giant grasses attain a height of about 

 80 feet and a diameter of more than half a yard. Of the 

 Graminece, or Grasses proper, there are between three 

 and four thousand known species, of which about 

 one hundred and twenty occur in Britain. The family 

 is grouped with the Sedges, Cyperacece, in the Order 

 Glumiflorce, which is defined as including grassy herbs 



