GRASS FAMILY 95 



J- 



flowered; lemma acuminate or awn-])ointed, scabrous, about 1 cm. long Prair- 

 ies and river valleys: Neb.— Tox.— Ariz.— B.C. Plain— MonL Je S. 



18. A. riparium Scribn. & Smith. Stem glabrous, erect, 4r-6 dm. high; 

 leaf-blades flat, becoming involute, 5-15 cm. long, 2-4 mm. wide, scabrous 

 throughout; spike 5-10 cm. long; spikelets 8-15, compressed, 5-7-flo\vered, 

 spreadmg, 5-6 mm. long; lemma oblong-lanceolate, acute, scabrous towards 

 the apex, acute or acuminate. River banks: Mont.— -Colo, SubmouL 



19. A. Smithii Rydb. Stem 3-10 dm. high; leaf-blades spreading, rigid, 

 bluish green, glaucous, smooth or minuteh scabrous benenth, becoming involute, 

 1-3 dm. long, 4-6 mm. wide; spikes 7-18 cm. long; spikelets 7-13-flowcrcd, some- 

 times m pairs; lemma S-12 nun. long, lanceolate, acute or acuminate, seldom 

 awn-pointed, smooth or nearly so. A. spicaiiim Scribn. & Smith, in part. .1. 

 ocndeniale Scribn. Blue-joint; Blue-stem. Prairies and plains: Man.— Mo. 

 — Tex. — Ariz. — Ore. — B.C. Plain—Mont. Je-S. 



20. A. moUe (Scribn. & Smith) Rv<lb. Stems 4-8 dm. high; leaf-blades 

 more or less glaucous, 1-3 dm. long, 2-4 mm. wide, at last involute, scabrous; 

 spike 1-2 dm. long, rather dense; spikelets about 2 cm. long, 6-8-flowered; 

 lemma 8-10 mm. long, densely hispidulous. River bottoms, especially in alka- 

 line soil: Sask.—N.M.— Utah— Wash. Plain— Mont, Jl-S. 



_ 21. A. lanceolatum Scribn. & Smith. Stem 6-10 dm. high, smooth and 

 shining; leaf-blades acuminate, 12-30 cm. long, 4-6 mm. wide, flat, scabrous 

 beneath, pilose above; spike 1-2 dm. long; spikelets 10-20 mm. long, 4-7-flowered, 

 erect; lemma 8-15 mm. long, broadly lanceolate, more or less short-pubescent. 

 Banks and meadows: Wash. — Ida.— Ore. Je-Jl. 



22. A. subvillosum (Hook.) E. Nelson. Stems 4-6 dm. high, slender, 

 glabrous; leaf-blades 1-2 dm. long, 2-^ mm. wide, flat or at last involute, scab- 

 rous; spike rather crowded; spikelets compressed, 12-15 mm. long: lemma 6-10 

 mm. long, obtuse or acute. River banks and sandy soil: Sask. — Neb.— Colo. — 

 Nev. — B.C. Plain — Mont, Je-Au. 



23- A. dasystachyum (Hook.) Scribn. Stem 3-10 dm. high; leaf-blades 

 5-20 cm. long, 2-6 mm. wide, flat, becoming involute in drj^ing; spike 6-18 cm. 

 long; spikelets slightly compressed, 4-8-flowered; lemma broadly lanceolate, 10- 

 12 mm. long, acute or rarely short-awned. Sand-dunes: Hudson Bay — Mich.— 

 ^^ is. — Ida.-— Sask. Plain — Boreal. Jl-Au, 



73. TRITICUM L. Wheat. 



Annuals or biennials with spicate inflorescence. Spikelets solitary at each 

 node, alternate, 2-5-flowered; flowers mostly perfect. Empty glumes with 

 one edge towards the rachis, broad, short, often toothed, but seldom awned at 

 the apex. Lemma ventricose on the back, several-nerved, often awned or at 

 least toothed at the apex. Palet shorter than the lemma, 2-keeled. Grain 

 deeply furrowed, free, pTibescent at the apex. 



Empty glumes distinctly keeled only at the apex; grain dull, neither glossy nor semi- 

 translucent. 1. r. aesthvm. 



Empty glumes distinctly keeled, almost winged, to the base; grain glossy, often some- 

 what translucent. 2. T. durum. 



1. T. aestivum L. Annual or biennial; stem about 1 m. high, hollow, 

 smooth; leaves at first rather light green, soft; spike 4-12 cm. long, 4-angled; 

 spikelets mostly 4-flowered; lemma with or without awn, T. sativum Lam. 

 Wheat, Old fields and waste places: cult, and rarely escaped. 



2. T. durum Desf. Annual or rarely biennial; stem 1 m. high or more, 

 usually with a pith; leaves smooth, whitish green, with hard cuticle; spike almost 

 terete, thicker than in the ordinary wheat, 5-10 cm. long; lemma long-a^uned. 

 Durum or Macaroni Wheat. Old fields and waste places: cult, and rarely 

 escaped. 



74. SECALE L. Rye. 



Annuals or biennials, with silicate inflorescence. Spikelets solitary at each 

 node, alternate, 2-flowered. Flowers all hermaphrodite and fertile. Empty 

 glumes subulate, a^\'n-pointedj with one edge towards the rachis. Lemma long- 



