GRASS FAMILY 55 



long, broadly lanceolate, acute; lemma minutely toothed at the apex. Moun- 

 tains: Wyo. — Colo. — ^N.M. Alont. — Subalp. Au. 



13. A. variabilis Rydb. Tufted, dwarf perennial; stem 1-2-leaved, 1-2 

 dm. high; basal leaves numerous, their blades 2-5 cm. long; stem-leaves somewhat 

 broader and often flat; panicle contracted, 3-6 cm. long, about 5 mm. wide; 

 branches erect or nearly so, usually short; empty glumes 2 mm. long, usually 

 more or less purplish, nearly equal, acute; lemma 1.5 mm. long, awnlcss. Moun- 

 tains: B.C. — Alta. — Colo. — Calif. Mont. — Subalp, Jl-S. 



14. A. idahoensis Nash. Tufted perennial; stem slender, 1-4 dm. high; 

 leaf -blades narrow, 4-9 cm. long, *l-2 mm. wide, flaccid, somewhat scabrous; 

 panicle oblong-ovoid, 5-12 cm. long, 2.5-4.5 cm. wide; empty glumes unequal, 

 1.5-2 mm. long, acuminate, purple; lemma two-thirds to three-fifths as long as 

 the first glume. A, ienuiculmis recta Nash. Mountain meadows: Wash. 

 Mont. — Colo. Suhmont. — Subalp. 



15. A. oregonensis Vasey. Tufted perennial; stem 3-6 dm. high; leaf- 

 blades 5-10 cm. long, 1-2 mm. wide, often involute; panicle 8-15 cm. long, often 

 nodding, flexuose; empty glumes purple, narrowly lanceolate, gradually acute; 

 lemma slightly shorter than the empty glumes, obtuse. Meadows: Wash. — • 

 Ore. — Wyo. SubnionL Jl-Au. 



16. A. oreophila Trin. Densely cespitose perennial; stems slender, 2-4 

 dm. high; leaf-blades filiform-setaceous, involute; those of the stem shjrhtly 

 broader, about 1 mm. wide, scabrous; panicle 1-2 dm. long; lower branches 5-10 

 cm. long; empty glumes slightly unequal, about 2 mm. long, pale or purple, 

 acute. A. hiemalis geminala Hitchc, in part. Mountains: Que. — Me. — N.Y. — 

 Pa.— Sask.— Colo.— Utah— B.C. Boreal— Mont.^Siibalp. Jl-S. 



17. A. hyemalis (Walt.) B.S.P. Tufted perennial; stem 2-8 dm. high; 

 leaf-blades 2-3 mm. wide, flat, 5-10 cm. long; panicle large and diffuse, 2-6 

 dm. long; spikelcts crowded at the ends of the branches; empty glumes nearly 

 equal, purplish or pale, about 2 mm. long, acute or acuminate; lemma obtuse, 

 two-thirds to three-fourths as long. A. scabra Willd. Open places: Lab. — 

 Fla. — -Calif .^ — -Alaska; Mex. Plain — Subalp. 



18. A. geminata Trin. Cespitose perennial; stem 2-3 dm. high, glabrous, 

 slender; leaf-blades about 0.5 mm. wide, 5-10 cm. long, the basal ones usually 

 involute; those of the stem-leaves usually flat; inflorescence 5-15 cm. long, 4-8 

 cm. wide; empty glumes about 3 mm. long, acute; lemma two-thirds to three- 

 fourths as long, obtuse, bearing at the middle of the back a straight awn. Wet 

 places: Alaska — B.C. Subalp. — Alp. Jl-Au. 



19. A, Bakeri Rydb. Cespitose perennial; stem about 3 dm. high, erect, 

 slightly geniculate below, glabrous; basal leaves numerous; leaf-blades flat, 1-2 

 mm. wide, 5-10 cm. long; panicle ovoid, 8-10 cm. long, open; empty glumes 

 nearly equal, purple, 2-2.5 mm. long, acuminate; lemma three-fourths as long, 

 obtuse, bearing above the middle a dorsal straight awn. Mountains: Colo. 

 Mont. 



20. A. zuelaleuca (Trin.) Hitchc. Cespitose perennial; stem erect, 2-5 dm, 

 high; leaf -blades flat, 1-2 mm. w^ide, 5-10 cm. long; branches of the panicle 

 flower-bearing to near the base; empty glumes copper-colored or purplish, lanceo- 

 late, gradually acute or acuminate, 2.5-3 mm. long; lemma slightly shorter, 

 bearing above the middle a straight awn. A, canina Rydb. (Fl. Colo.) Wet 

 places: Alaska — B.C. — Colo. Mont, — Subalp. Jl-Au. 



31. CALAMAGROSTIS Adans. Reed-grass. 



Erect perennials. Inflorescence paniculate. Spikelets numerous, 1-flowered; 

 flowers perfect; the rachilla usually produced beyond the flower; the prolonga- 

 tion with a hair-pencil. Empty glumes 2, persistent, narrow, keeled, acute or 

 acuminate. Lemma much shorter, thickly hyaline, with a basal ring of long 

 hairs, and a dorsal a.vm, Palet small, narrow, thin, hyaline. Styles short, dis- 

 tinct; stigmas plumose. 



