260 



GRAMINEAE. 



VOL. I. 



Prairie or Bunch Spear- 

 Fig. 625. 



22. Poa arida Vasey. 

 grass. 



Poa andina Nutt. ; S. Wats. Bot. King's Exp. 388. 1871. Not 



Trin. 1836. 



Poa arida Vasey, Contr. U. S. Nat. Herb, i: 270. 1893. 

 Poa pratericola Rydb. & Nash ; Rydb. Mem. N. Y. Bot. Card. 



i : 51. 1900. 



Culms i-2 tall, erect, rigid, simple, smooth and gla- 

 brous. Sheaths usually overlapping, smooth or somewhat 

 roughish; ligule i"-2" long, acute; blades smooth beneath, 

 rough above, i"-i" wide, flat or folded, pungently pointed, 

 those of the culm i'-i' long, erect, the basal leaves 3'-6' 

 long; panicle contracted, 2'-$' in length, the branches erect, 

 spikelet-bearing nearly to the base, ii' long or less; spike- 

 lets 4-7-flowered, 2\"-?>\" long; lower scales nearly equal, 

 acute, 3-nerved; flowering scales ii"-2" long, erose-trun- 

 cate at apex, strongly silky-pubescent on the nerves for 

 half their length, the lower part very pubescent between 

 the nerves; intermediate nerves very obscure. 



On prairies, Kansas to Utah, Wyoming, North Dakota and Manitoba. July-Sept. 



23. Poa Buckleyana Nash. Buckley's Spear- 

 grass. Fig. 626. 



Poa temiifolia Buckley, Pfoc. Acad. Phila. 1862: 96. 1862. 



Not A. Rich. 1851. 

 Poa Buckleyana Nash, Bull. Torr. Club 22: 465. 1895. 



Culms 6'-2 tall, erect, rigid, simple, smooth and 

 glabrous. Sheaths shorter than the internodes; ligule 

 2"-3" long, acute; blades i'~4' long, about i" wide, 

 erect, flat, or becoming involute, smooth or rough ; 

 panicle i'~4' in length, contracted, the branches erect, 

 li' long or less, spikelet-bearing nearly to the base; 

 spikelets 2-s-flowered, 2"-3" long; scales acute, the 

 lower nearly equal, scabrous on the keel ; flowering 

 scales about 2" long, obtuse or acutish, sparingly pubes- 

 cent on the nerves below, sometimes slightly hispid 

 toward the base between the nerves. 



South Dakota to Kansas, California and British Columbia. 

 Bunch Red-top. Oregon Blue-grass. July-Aug. 



24. Poa laevigata Scribn. Smooth Spear- 

 grass. Fig. 627. 



Poa laevis Vasey, Contr. U. S. Nat. Herb, i : 273. 

 1893. Not Barb. 1877. 



Poa laevigata Scribn. Bull. U. S. Dep. Agr. Agrost. 5: 

 31- 1897. 



Culms densely tufted, ii-2i tall, erect, slender, 

 the innovations 4'-8' long; sheaths smooth and gla- 

 brous; ligule \\"-2" long, glabrous; blades narrow 

 and involute, 4' long or less ; panicle slender, 3'-6' 

 long, its larger branches i'-2' long; spikelets 2\"- 

 3i" long, 3-4-flowered, the flowering scales ii"-2" 

 long, hispidulous all over, obtuse to acutish. 



On dry hillsides and in meadows, Quebec to Wash- 

 ington, south in the mountains to Colorado. June- 

 Aug. 



