498 



ILLUSTRATIONS OF THE NATURAL ORDERS. 



hilum (Fig. 126-128, G22 - G24). — i2!r. Agrostfa, Phleum, Poa, 

 Festuca, which arc the principal meadow and pasture grasses : Ory- 

 za (Rice), Zea (Maize), Avena (the Oat), Triticum (Wheat), Sccalc 

 (Rye), llordeum (Barley), are the chief cereal plants, cultivated for 

 their farinaceous seeds. This universally diffused order is one of 

 the largest of the vegetable kingdom, and doubtless the mo^t impor- 

 tant ; the floury albumen of the seeds and the nutritious herbage 

 constituting the chief support of man and the herbivorous animals. 

 No unwholesome properties are known in the family except in the 

 grain of Darnel, which is deleterious. Ergot, or Spurred Rye, is 

 no exception, being a morbid growth, caused by a parasitic fungus. 

 The stems of grasses frequently contain sugar in considerable quan- 

 tity (especially when they are solid) ; as in Maize, the sweet variety 

 of Sorghum vulgare, or Broom-Corn, and in Sugar-Cane (Saccharum 

 officinarum), which affords the principal supply of this article. 



\M 



TIG 1260. Or.c-flowered spikelet or loensta of Alopecurus, with the glumes fcparated. 

 1267. Same with the glumes removed : an aunt on the back of the outer palea. 12G8 Onc- 

 flawered spikelet of an Agrostis 1269. Pistil of a Grass, showing the two feathery stigmas, 

 and the two h} pogynous sc;iles or squamulse, larger than usual (representing the perianth). 

 1270. Two-flowered spikelet of an Avcna ; with the glumes spreading. 1271 Oce of the flow- 

 ers with its palea; ; the exterior pointed, with two bristles or cusps at the apex, and with a 

 bent awn on the back 1272. Many-flowered spikelet of Glyceria lluitans. 1273 An enlarged 

 separate flower of the same, seen from within, showing the inner paleae, &c 1274. The fruit 

 (ear) opsis) of the Wheat, with an oblique section thtonsh the integuments of the embryo, 

 which is exterior to the albumen. 1275 Detached magnified embr.o : n. the imperfect cotyle- 

 don ; 6, the first leaf of the plumule; c the second leaf of the plumule ; </, the radicle. 127G 

 The can opsis of Ilordenm (Barley;. 1277. A cross-section 1278 A vertical section, show- 

 ing the external embryo at the base 1279 Magnified detached embryo, with its broad cotyle- 

 don and the plumule. 12S0. Moie magnified vertical section of the same: a, the plumule ; b, 

 the radicle. 



