44 BULLETIN 772, U. S. DEPARTMENT OF AGRICULTURE. 



The name Kentucky bluegrass has been used because in Kentucky 

 the bluegrass pastures have been a prominent feature of the agricul- 

 ture of the State. In the northern portion of its range it is usually 

 called June-grass. Bluegrass flourishes as far west as eastern Ne- 

 braska and as far south as Virginia and in the mountains to northern 

 Alabama. In the valleys of the western mountains and in the humid 

 region of the Pacific coast, from northern California to British 

 Columbia, bluegrass is the common pasture grass. In the regions 

 where bluegrass is used for pasture it is the standard lawn grass. 

 By liming the soil and by artificial watering bluegrass may be grown 

 for lawns beyond the limits outlined above, but it can not be made 

 to thrive in the warmer parts of the Southern States or in the arid 

 regions of the Southwest. 



Poa compressa L. (PL IV), cultivated under the name of Canada 

 bluegrass, is of some commercial importance, being grown in the 

 region that is adapted to the growth of Kentucky bluegrass, but it 

 is used chiefly on sterile sandy or clay soils where the latter species 

 does not thrive. Canada bluegrass differs from Kentucky bluegrass 

 in its blue-green color, distinctly compressed stems, and narrow less- 

 branched panicles. It produces abundant rhizomes that throw up 

 numerous scattered stems, mostly 6 to 15 inches tall, these being 

 usually solitary rather than tufted. On account of its wiry, com- 

 pressed stems it is called in some localities wire-grass and flat-stem. 



Two other species of Poa occasionally grown but of little agricul- 

 tural importance are Poa trivialis L., rough-stalked meadow grass, a 

 species lacking rhizomes, but resembling P. pratensis in its panicle, 

 distinguished easily by its backwardly roughened sheaths; and Poa 

 palustris L. (P. triflora Gilib., P. serotina Ehrh.) known to seedsmen 

 as fowl meadow grass, a smooth, rather tall, tufted grass, differing 

 from bluegrass in the absence of rhizomes, in the larger more open 

 panicle, and in the smaller, 2 to 4 flowered spikelets. 



Poa arachnifera Torr., Texas bluegrass, has been used in some of the 

 Southern States as a winter pasture grass and as a lawn grass. It is 

 an erect dioecious grass, 1 to 2 feet high, with strong rhizomes and 

 narrow panicles, 2 to 4 inches long, the staminate spikelets glabrous, 

 the pistillate spikelets with a copious tuft of woolly hairs at the base 

 of the florets. Texas bluegrass is a native of Oklahoma and Texas. 



Poa annua L., annual bluegrass (PI. V), is a low, soft, light-green, 

 annual grass that is frequently found as a weed in lawns and gardens. 

 It thrives in the spring or even in the winter in southerly regions, 

 forming fine light-green patches, which die out later in the season, 

 leaving unsightly spots. Poa annua is a native of Europe, but is 

 widely introduced in America. 



Several species are important range grasses. Malpais bluegrass 

 (Poa scabrella], a bunch grass, with slightly roughened sheaths and 



