204 



GRAMINEAE. 



8. Poa pratensis L,. Kentucky Blue-grass. June Grass. (Fig. 466.) 



Poa pratensis L. Sp. PI. 67. 1753. 

 Poa pratensis var. angustifolia Kunth, Enum. i: 353 

 1833- 



Glabrous, culms i-4 tall, from long running 

 rootstocks, erect, simple, smooth. Sheaths often 

 longer than the internodes; ligule ^" long or less, 

 truncate; leaves smooth or rough, YZ"-'-," wide, 

 those of the culm 2 / -6 / in length, the basal much 

 longer; panicle 2^ / -8 / in length, usually pyram- 

 idal, the branches spreading or ascending, some- 

 times flexuous, i / -3 / long, divided and spikelet- 

 bearing above the middle; spikelets 3-5-flowered, 

 2 // -2)4 // long, exceeding their pedicels; scales 

 acute, the lower unequal, glabrous, rough on 

 the keel, the lower i -nerved, the upper 3-nerved; 

 flowering scales IJ4" long, webbed at the base, 5- 

 nerved, the marginal nerves and midnerve silky- 

 pubescent below, the intermediate ones naked. 



In meadows, fields and woods, almost throughout North America. Widely cultivated for hay 

 and pasture. Also in Europe and Asia. In North America probably indigenous only in the northern 

 and mountainous regions. Variable. June-Aug. 



9. Poa pseudopratensis Scribn. & Ryd. 

 Prairie Meadow-grass. (Fig. 467.) 



Culms i-2% tall, erect, simple, smooth and 

 glabrous. Sheaths shorter than the internodes, 

 smooth or slightly rough; ligule 2" long, acute, 

 decurrent; leaves i // -3 // wide, smooth beneath, a 

 little rough above and on the margins, those of 

 the culm 1'-?,%' long, the basal 6'-io' in length; 

 panicle 2'-$' long, open, the branches spreading 

 or ascending, i / -2 / long; spikelets 3-5-flowered, 

 3 // ~4 // long, exceeding their pedicels; lower scales 

 nearly equal, acute, 3-nerved ; flowering scales 

 acutish, about \W long, rough above, 5-nerved, 

 pubescent between the nerves below, the marginal 

 nerves and midnerve silky-pubescent about half 

 their length. 



Manitoba and Assiniboia to Nebraska and Colorado. 





10. Poa trivialis L,. 



Roughish Meadow-grass. (Fig. 468.) 



Poa trivialis ~L,. Sp. PI. 67. 1753. 



Culms i-3 tall, usually more or less decumbent 

 at the base, simple, smooth or slightly scabrous. 

 Sheaths usually shorter than the internodes, rough; 

 ligule 2 // ~3 // long, acutish; leaves 2'-~' in length, 

 \"-2 ff wide, generally very rough; panicle 4 '-6' long, 

 open, the branches usually spreading or ascending, 

 \'-2' long; spikelets 2- or sometimes 3-flowered, i W 

 long, exceeding their pedicels; scales acute, the empty 

 basal ones rough on the keel, the lower i -nerved, 

 shorter than the 3-nerved upper; flowering scales T '- 

 i%" long, webbed at the base, 5-nerved, the mid- 

 nerve silky-pubescent below, the lateral nerves 

 naked, the intermediate ones prominent. 



In meadows and waste places, New Brunswick to 

 Michigan and Virginia. Naturalized from Europe. 

 June-Aug. 



