GRASS FAMILY 79 



at the base, purple in the midflle and brownish-scarious at the top. P. phoenicia 

 Rydb. Mountains: Colo. Alp, Au, 



33. P. pratensiformis Rydb, Stem 3-6 dm. high; leaf-blades flat, 2 6 



mm, wide, those of the stem 2-7 cm. long, those of tlie sterile shoots 1.5-3 dm. 

 long, scabrous on the margins; panicle 5-12 cm. long, spreading in anthosis 

 only; spikelets 3~5-flowered, 6-8 mm. long; empty glumes nearly equal, acute; 

 lemma obtuse, silky-hairy on the nerves to the middle and pubescent all over 

 near the base. P. pseudopratensis Scribn. & Rydb., not Beyer. Wet places: 

 S.D. — -Kans. — Utah. Plain — Submorit. Je-Jl. 



34. P. arida Vasey. Stem 2-6 dm. high; leaf-blades 2-15 cm. long, erect, 

 flat, or becoming somewhat involute, striate; panicle narrow, dense, 7-15 cm. 

 long; branches erect; spikelets 6-7 mm. long, 5-9-flowered; lemma obtTise, 

 scarcely compressed. P. aruKna Nutt. P, pratericola Rydb. Praines and 

 meadows: Kan.— N.M.— Utah— Wyo. Plain— Subalp. 



35. P. Sheldon! Vasey. Stem rigid, 2-3 dm. high, smooth; blades of the 

 basal leaves 5-10 cm. long, 2-3 mm. wide, rigid, flat or conduphcate; panicle 

 narrow, 3-7 cm. long; spikelets about 6 mm. long, 3-4-flowered; lemma 4 mrn. 

 long, subobtuse, short-pubescent near the base, scarious at the apex. Dry hills: 

 Colo. — Wyo.— Utah. Mont. — Subalp, Je-Jl. 



36. P. glaucifolia Scribn. & Williams. Stem about 6 dm. high, smooth, 

 except at the nodes; leaf-blades flat, glaucous, 1.5-2 dm. long, 2-4 mm. widej 

 panicle open; spikelets compressed, 3-4-flowered; empty glumes ovate, obtuse or 

 acutish, 3-nerved, scabrous on the back, about 4 mm. long; lemma obtuse, 

 pubescent on the keel and nerves, 3-4 mm. long. Moist banks: S.D.— Colo.— 

 Mont. Submont. — Mont, Jl-Au. 



37. P. rupicola Xash. Stems 1-3 dm. high, erect, rigid ; ligules ovate, 2 mm^. 

 long; leaf-blades 1-4 cm. long, about 1 mm. wide, erect, involute; panicle 2-o 

 cm. long, with short ascending branches; spikelets 2-4-flowered, 3-5 mm. long, 

 purple; lemma with midvein and lateral nerves pubescent below, otherwise 

 glabrous or scabrous. P. rupestris Vasey. High mountains: Mont. — Colo.^ 

 Utah— Ore. Mont, — Alp, Jl-Au. 



38. P. Pattersoni Vasey. Stem 5-40 cm. high; ligules 1 mm. long, trun- 

 cate; leaf-blades 1-15 cm. long, about 1 mm. wide, conduphcate or flat, smooth; 

 panicle dense; spikelets 4-6 mm. long, 2-5-flowered, purple; lemma pubescwit 

 on the keel and lateral veins below, otherwise glabrous. P. Grayana Rydb. (Fl. 

 Colo.), not Vasey, a large form. High mountains: Colo. — Wyo. — Uta^. Alp. 

 Jl-Au. 



39. P. Lettermani Vasey. Stem 2-10 cm. high; ligules acute; leaf-blades 

 mostly flat, 1-3 cm. long, 1-2 mm. wide; panicle 1-3 cm. long, dense, narrow; 

 spikelets 3-4 mm. long, 2-4-flowered, purplish; lemma 2 mm. long, ovate, acute, 

 obscurely nerved, glabrous. P. Brandegei Scribn. Alpine peaks: Colo.— Wyo. 

 — (? Wash.) Alp, Au. 



40. P. Multnomae Piper. Stems 1-4 dm. high, very slender, glabrous; 

 ligules 1-2 mm. long; leaf-blades narrow, flat or conduphcate, 8-12 cm. long, 1-2 

 mm. wide; panicle loose, 5-10 cm. long, usually pale green; spikelets 5-7 mm. 

 long 3-5-flowered; lemma narrow, lanceolate, glabrous, shghtly puberulent on 

 the keel and marginal veins below. Cliffs: Ore.— Wash.— Mont. Submont. 

 J^Jl. 



41. P. paddensis Williams. Stem erect, 3-5 dm. high, smooth; leaf -blades 

 5-8 cm. long; panicle erect, dense, oblong, 4-8 cm. long; spikelets about S mm. 

 long, 3-5-flowered, purple; empty glumes broadly scarious-margmed, about 4 

 mm.' long; lemma 6 mm. long, minutely scabrous and villous at the base. P. 

 purpurascens Vasey, not Spreng. P. subpurpurea Rydb. Mountains: B.C. — 

 Alta.— Colo.— Wash. Alp. Jl-Au. 



42. P. Cusickii Vasey. Stem smooth, erect, 3-5 dm. high; basal leaf-blades 

 filiform, 1 mm. wide, 7-12 cm. long; those of the stem-leaves 5-7 cni. long, erect; 

 ^^^^^1^ ^^^.o r^K^r^Tl<r .^-10 PTTi lonff! smkclets 8-10 mm. lone, 3-5-ilo wered ; 



