GENERAL DESCRIPTION OF GRASSES. 



A grass possesses the following parts : (1) The root, (2) the stem, (3) 

 tbe leaves, (4) the flowers. 



(1) The roots are the fibrous branching organs which extend down- 

 ward into the ground and appropriate the water or other liquid nutri- 

 ment to be conveyed into the stem and leaves. 



(2) A stem that rises above ground, either erect, ascending, or re- 

 clining, is called a culm. In some species, in addition to tbe culm, 

 there are horizontal subterranean stems, improperly called roots. They 

 are known botanically as rhizomes, and are sometimes several feet long. 

 They may be distinguished from the true roots by their bearing a 

 greater or less number of scales and sending out erect branches as 

 well as fibrous roots. In some grasses there is a kind of bulb at the 

 base of the stem, in which is stored a concentrated mass of food for 

 the support of the plant under peculiar circumstances, as in protracted 

 drought. This bulbous formation is a part of the stem, and not of the 

 root. The stem or culm of grasses is usually cylindrical and hollow; 

 sometimes it is more or less compressed or flattened. It is divided at 

 intervals by transverse thickened portions called joints or nodes, at 

 which points leaves and sometimes branches are given off. These 

 nodes tend also to strengthen the stem. Stems are usually simple and 

 uubranched, except at the top, where they commonly divide into the 

 more or less numerous branches of the panicle or flowering part. But 

 some steins give rise from the side joints to leafy branches, which may, 

 like the main stem, produce smaller panicles at the top. 



(3) The leaves take their origin at the nodes or joints in two ranks 

 that is, they are placed alternately on opposite sides of the stem at 

 greater or less distances ; thus, the first leaf will be on one side, the 

 second on the opposite side a little higher up, the third still higher and 

 directly over the first, the fourth over the second, and so on. The leaves 

 consist of three parts: (1) the sheath, (2) the ligule, and (3) the blade. 

 The sheath is that part which clasps the stem. It is generally open on 

 one side, as will be readily observed in the leaves of a corn-stalk, but in 

 some grasses the slieath is partly or even completely closed together 

 by the adhesion of the opposite edges. The sheath is analogous to the 

 stem or petiole of the leaves of many higher plants. At the point where 

 the blade of the leaf leaves the stem, at the top of the sheath and o 



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