POACEAE. 43 



Internerves of the ovate flowering glumes pubescent ; innovation several, both 

 extra- and intra-vaginal. 28. P. pseudopratensis. 



XII. EPILES. 



Flowering glumes about 5 mm. long, strongly purple-tinged, but slightly scabrous ; 

 stem-leaves broad. 29. P. subpurpurea. 



Flowering glumes about 4 mm. long or less, usually greenish or slightly purple ; 

 stem-leaves narrow. 30. P. epilis. 



XIII. FILIFOLIAE. 



One species. 31. P. nematophylla. 



XIV. FENDLERIANAE. 



Ligules 5-7 mm. long, acute or acuminate. 32. P. longiligula. 



Ligules short, rounded or truncate at the apex ; those of the innovations obso- 

 lete. 



Panicle very narrow and long-peduncled, contracted. 33. P. longipedunculata. 

 Panicle more open at least in anthesis. 



Flowering glumes narrowly oblong ; leaves very slender and rough. 



34. P. scabrinscula. 

 Flowering glumes ovate. 



Panicle very short ; plant low ; leaves smooth below, scabrous above. 



35. P. brevipaniculata. 

 Panicle longer ; plant 3-6 dm. high ; leaves scabrous below, hispid-puberu- 



lent above. 36. P. Fendleriana. 



XV. BUCKLEYANAE. 



Internerves of the flowering glumes glabrous ; nerves silky. 



Plant low ; leaves stiff, involute and often arcuate. 40. P. juncifolia. 



Plant tall ; leaves broad and flat. 37. P. glancifolia. 



Internerves of flowering glumes more or less scabrous or strigose. 

 Flowering glumes merely scabrous throughout. 



Empty glumes strongly nerved, elongated lanceolate, almost equalling the 

 oblong, very scabrous flowering glumes ; leaves usually broad (2-3 mm.) 

 and flat ; ligules lanceolate, acute. 38. P. nevadensis. 



Empty glumes not strongly nerved, ovate-lanceolate, usually much shorter 



than the flowering glumes, which are broader and less scabrous. 

 Ligules narrowly lanceolate, 3-4 mm. long, acuminate ; stem-leaves very 



narrow and involute. 39. P. laevigata. 



Ligules short, 1-2 mm. long, triangular or broadly ovate and acutish or 



truncate. 

 Plant 2-4 dm. high ; leaves mostly basal and stiff, short, seldom 8 cm. 



long ; ligules rounded. 40. P. juncifolia. 



Plant 4-10 dm. high, leafy throughout; leaves longer. 

 Ligules ovate or rounded, acute or obtuse ; leaves soft. 



41. P. con f lisa. 



Ligules very short, truncate ; leaves rather firm. 42. P. truncata. 



Flowering glumes more or less strigose on the lower portion, scabrous above. 



Flowering glumes not longer than the empty glumes, ovate ; pubescence much 



longer on the nerves. 43. P. pratericola. 



Flowering glumes oblong, longer than the empty glumes ; pubescence on the 



nerves scarcely stronger than that on the internerves. 

 Ligules ovate or rounded, obtuse or acutish. 41. P. confusa. 



Ligules lanceolate, acuminate. 



Plant yellowish green ; leaves all filiform, soft and usually involute. 



44. P. lucida. 

 Plant dark green, leaves broader, flat or conduplicate ; at least those of 



the stem firm. 



Creeping rootstock none ; panicle dense ; flowering glumes greenish 

 at the base and purple above ; leaves usually narrow and con- 

 duplicate. 45. P. Buckleyana. 



