GRASS, in botany. The tribe of grass es in one of the seven natural families in to which all vegetables are distributed by Linnaeus, in his " Philosophia Botanica." They are defined to be plants which have very simple leaves, a jointed stem, a husky calyx, named a Blume, and a single seed. This description includes corn as well as the grasses.
Most of these plants are annual or pe rennial herbs ; some of them are erect, others creep upon the ground. The roots, in the greatest number creep, and emit fibres from each knot or joint ; in others, they are simply branched and fibrous. The stems and branches are round : the leaves are simple, alternate, entire, very long; and commonly narrow ; they are generally placed immediately upon the stem, except in the bamboo, and a few others, which have a foot stalk at the origin of the leaves. The leaves form below a sort of sheath, which em braces the stem, and is generally cleft on one side through its whole length. The top of the sheath is sometimes crowned with a membrane, that is either cleft or entire, and is frequently accompanied with two appendages or ears, as in rice, pharus, darnel, wheat, rye, and barley. In others, the sheath is crowned with hairs, as in millet, panic-grass, and andro pogon, and in some species of panic grass it is naked,that is, has neither mem brane nor hairs. There are three sec tions. The flowers are hermaphrodite in plants of the first section ; male and female upon the same root in those of the second ; hermaphrodite and male on the same root in those of the third. They proceed either singly from the sheath of the leaves, as in lygeum ; form a single spike, as in nardus and darnel ; or are formed into a panicle, that is, loose spike, as in poa, agrestis, and oats. The calyx
and corolla in this order are not suffi ciently ascertained. In some a single scale or husk, in others two, as in nardus, supply the place of both covers ; some grasses, as canary-grass, and phleum, have four husky scales, two of which serve for the calyx, and the other two for the corolla ; some have five, as anthoxan thum ; others six, as rice, four of which are supposed to constitute the calyx, and the other two are termed, improperly enough, the husky petals. The corolla is sometimes composed of one petal with two divisions, as in fox-tail grass. The stamina are generally three in number, and placed irregularly with respect to the situation of the calyx and corolla. One stamen is commonly placed betwixt the seed bud and the two small scales or external husk of the corolla ; and two be twixt the seed bud and the inner husk. Rice, zizania, and pharus, have six stami na. The anthers are long, furnished with two cells, and slightly attached to the filaments. The seed bud is placed upon the same receptacle as the calyx, corolla, and stamina. In bobartia it is said to be placed under the receptacle of the flower. The style is generally dou ble, and crowned with a hairy stigma or summit. The seed vessel in this order is wanting. The seeds are single, oval, and attached below to the bottom of the flower.