GRASS FAMILY. 



373 



ceeds harvest ; and thus the gTOuncl is left exposed to the injurious in- 

 fluence of the scorching- sun. The clover, hov.-ever, when present in suf- 

 ficient quantity, soon springs up and affords a shelter to the soil ; and, 

 when the land is good, the green grass (Poa pratensis, L.), comes in, 



spontaneously, as the clover disappears. The seed, of Timothy, is 

 usually sown in autumn, — among, and immediately after Wheat and 

 Rye ; though it answers very well, when sown early the ensuing spring. 



6. AGROS'TIS, L. Bext-grass. 



[Greek, Agros, a field ; its usual place of growth.] 



Spikelets in an open panicle, l-flowered. Glumes nearly equal, often 

 longer than the pales, pointless. PalecB very thin, pointless, naked at 

 the base; the lower 3-5-nerved, sometimes awned on the back, the 

 upper often minute or wanting. Stamens usually 3. Mostly perennials 

 with slender caespitose culms. 



1. A. vulga'ris, With. Culms slender, mostly erect; leaves lance- 

 linear ; panicle loose, ovoid-oblong in its outline, — usually purple ; pa- 

 leae awnless, — the lower one twice the size of the upper one ; ligule 

 truncate, very short. 



Common Agrostis. Herd-grass (of Penn.) Red-top. 



Root perennial, creeping. Culms ctespitose, very slender, erect or ascending, 1-2 feet 

 high. Leaves 3-6 or 8 inches long, nerved, scabrous ; sheaths striate, smooth. Panide 

 mostly purple — the branches capillary, alternatingly semi-verticillate, smoothish or often 

 scabrous. Glumes smooth, except on the keel, lanceolate, acute, finally expanding. 

 Paleoi membranaceous, smooth at base, — the lower one nearly as long as the glumes, 

 the upper one very small, retuse. 



Pastures and moist meadows : introduced. Xative of Europe. Fl. July. Fr. August. 



Obs. This grass is somewhat variable in its botanical characters, — 

 as may be inferred from one of the specific names it has received, viz. : 

 A. polymorpha. It is often cultivated in some districts of the country, 

 and answers a tolerably good purpose in wet or swampy meadows, which 



Fig. 253. A spikelet of Timothy (Phleum pratense). 254. The floret removed from the 

 glumes. 



