CLASS TRIAJ^DRIA. 



135 



on the indented stem, or rachis, each calyx containing three or 

 four flowers : the central ones, for Avant of room to expand, arc 

 rendered infertile, the two outer ones only producing grain. 

 The calyx glume, from the magnitude of the seed, becomes broad 

 and boat-shaped, terminated simply by a point, or else by an 

 awn ; the larger valve of the corolla also ends in a bristle. 

 Nearly all the wheat cultivated is of but one species, and now 

 known to produce many permanent varieties. The plants of 

 the grass family which are used as food for man are wheat, rye, 

 barley, and Indian corn ; the latter is separated from its natural 

 alliances by the artificial system, and placed in the class Mo- 

 noecia, because the stamens and pistils are found in different 

 flowers growing from the same root. The styles, long, slender, 

 and exserted^ form what is called the silk ; they are thus favor- 

 ably situated for receiving the fertilizing pollen which is show- 

 ered down from the staminate flowers. 



^ 176. The fruit of wheat, rye, &c., is called grain. Grain con- 

 sists of the seed with its ^^ericarp ; these are not easily distin- 

 guished from each other till the grain is ground into flour ; the 

 pericarp separating from the seed then forms what is called the 

 hran; and the seed, the flour or meal. The sugar-cane (Sac- 

 CHAKUM officinavxim'^) is supposed to have been brought from 

 the South of Europe to the West Indies. The stem or culm, 

 which sometimes grows to the hight of twenty feet, affords the 

 juice from wdiich sugar is made. The bamboo (Arundo hamhos) 

 of the East Indies is a species of reed, which is said to attain 

 in some situations the hight of sixty feet. 



The sedge {Carex) is a gramine- 

 ous plant, but as it bears stamin- 

 ate and pistillate flowers, is placed 

 in the class Monoecia. Tlie carices 

 (plural of carex) constitute a very 

 numerous family of plants. 



Fig. 131 represents two magni- 

 fied flowers of the orchard-grass 

 (Dactylis glomerata)\\ at a is a ca- 

 lyx:}: composed of two valves; these 

 are compressed, keeled,^ acute ; one 

 valve is shorter than the valves 

 of the flowers, the other longer ; 

 the calyx is common to the two 

 flowers ; b shows the valves of the corollas ; they are oblotig and acute ; c repre- 



• See Appendix, Plate ii. Fig. 2. 



t Glomerata signifies a cluster, alluding to the crowded panicles of flowers. 



X The pans of the calyx, and also of the corolla, are sometimes called glumes ; they are all much 

 alike in appearance, being merely a set of sheaths, for the purpose of protecting the stamens : they are 

 not distinguished by any difference in color from the leaves or stem. The anthers, which are usually 

 yellow, are the only part of the flower of the grasses which is colored, 



§ Resembling the keel of a boat. 



What is said of Indian corn 2— Grain— Sugar-cane— Bamboo— Sedge ?— What docs Fi^'. I'M npro- 

 sont? 



