228 A TEXT-BOOK OF GRASSES 



most important genera of forage grasses. The species are 

 abundant in the grazing areas of our western mountains 

 and several species are cultivated. 



252. Kentucky blue-grass. — Culms from a few inches 

 to 2 feet or more in height from slender creeping rhizomes; 

 sheaths smooth; ligule short; blades flat or somewhat 

 folded, ending like most species of the genus, in a boat- 

 shaped blunt point, panicle 2 to 4 inches long or sometimes 

 larger, pyramidal, open, the lower branches in groups of 

 about 5; spikelets 3- to 5-flowered, 4 to 5 mm. long; lemmas 

 pubescent on the keel and marginal nerves, bearing a 

 tuft of cobwebby hairs at base. Commonly cultivated as 

 a lawn- and pasture-grass. 



Poa pratensis L. (Fig. 54.) Kentucky blue-grass. Perennial, in 

 tufts but producing slender creeping rootstocks; culms slender, 

 erect, smooth, terete or slightly flattened, 1 to 3 feet high; sheaths 

 smooth, sometimes slightly keeled; ligule membranaceous, short, 

 truncate, about 1 mm. long; blades, especially the basal, long and 

 narrow, flat or usually partly folded or conduplicate, usually not 

 over 4 mm. wide, the uppermost 1 to 3 inches long, appressed, 

 shghtly roughened on the margins and keel, especially toward the 

 boat-shaped tip; panicle open, pyramidal or oblong, 3 to 6 inches 

 long, the scabrous branches naked below, the lower in whorls of 

 usually 5, one being stronger; spikelets ovate or lanceolate, flat- 

 tened, 4 to 6 mm. long, usually 3- to 5-flowered, the ultimate pedi- 

 cels about 1 mm. long; glumes narrow, acute, the first 1-nerved, 

 the second 3-nerved; lemma 5-nerved, acute, hyaline or papery and 

 often purple-tinged at apex, about 4 mm. long, the keel and margi- 

 nal nerves pubescent, the base bearing a tuft of cobwebby hairs. 

 The boat-shaped apex of the blades is characteristic of the genus. 

 Blue-grass is a native of Europe and may also be native in the 

 northern parts of North America. In open dry or sterile soil the 

 flowering culm may be only a few inches in height. In color the 

 foliage is a dark green and does not have a blue color as the name 

 would indicate. As it flowers in June, the name June-grass is 

 applied to this species in parts of the northern United States. 



