GRASS FAMILY 79 



at the base, purjile in the middle and brownish-scarious at the top. P. Phoenicia 

 Rydb. Mountains: Colo. Alp. Au. 



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

 nmi. wide, tho.se of the stem 2-7 cm. long, tho.se of the sterile shoots 1.5-3 dm. 

 long, scabrous on the margins; panicle 5-12 cm. long, si)reading in anthesis 

 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. <t Rydb., not Beyer. Wet places: 

 S.D. — Kans. — -Utah. Plain — Submont. 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 obtuse, 

 scarcely compressed. P. andina Nutt. P. praiericola Rydb. Prairies and 

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



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

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

 narrow, 3-7 cm. long; s{)ikelets about 6 mm. long, 3-4-flowered; lemma 4 mm. 

 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. wide; 

 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 2-5 

 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. Patterson! Vasey. Stem 5-40 cm. high; ligules 1 mm. long, trun- 

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

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

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

 Colo.), not Va.sey, a large form. High mountains: Colo. — Wyo. — Utah. 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 conduplicate, S-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, glafjrous, slightly puberulent on 

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

 Je-Jl. 



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

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

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

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

 purpura.scens 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 cm. long, erect; 

 panicle dense, oblong, 3-10 cm. long; spikelets 8-10 mm. long, 3-5-flowered; 



