168 



191. H. pusiUum. 

 Three spikelets x 3. 



192. H. nodosum. 



wide ; lateral pair of spikelets each reduced to 1-3 spreading awns ; glumes cf 

 perfect spikelets awn-like, 3-6 c?n. long, spreading ; lemma 6-8 mm. long, with 

 an awn as long as the glumes ; all the awns very slender, 

 scabrous. Coast, Lab. to X. J. ; prairies and waste ground, 

 Ont. to 111., Kan., and westw. June-Aug. Often a trouble- 

 some weed. (Eurasia.) FIG. 190. 



2. H. pusillum Nutt. Annual. 1 i dm. high; leaves 6 cm. 

 or less long, erect, scabrous ; spikes erect, 2-7 cm. long, 

 1-1.5 cm. wide; lateral pair of spikelets 



abortive ; first glume of each, and both 

 glumes of fertile spikelet, dilated above the 

 base, attenuate into a slender awn 8-15 mm. 

 long, equaling the awned lemma. Plains, 

 especially in saline soil, O. to Mo., and 

 westw. ; sparingly introduced, D. C., Va., 

 and southw. along the coast. May, June. 

 FIG. 191. 



3. H. nodbsum L. Similar to the pre- 

 ceding, usually taller ; spike 2-8 cm. long, 

 about 1.5 cm. wide ; all the glumes aicn- 

 like. 1-1. 5 mm. long. Thin dry soils, Ind., 



Minn., and north w., s. to Tenn. and Tex. (Eurasia.) FIG. 

 192. 



4. H. Pammeli Scribn. & Ball. Perennial, erect or geni- Three spikelets x 3. 

 culate at base, 6-10 dm. high ; leaves 1.2-2 dm. long. 5-8 mm. 

 wide, long-acuminate, scabrous ; spikes nodding, 8-17 cm. long, 2-3 cm. wide ; 

 the lateral pair of spikelets nearly sessile, perfect ; the middle spikelet 2-floicered 

 or often with the rudiment of a third floret; glumes 2.3-3.5 cm. long, subulate- 

 attenuate into slender awns. Prairies, 111., la., S. Dak., and Wyo. June- 

 Aug. Intermediate between Hordeum and Elymus ; closely related to culti- 

 vated barley. 



81. ELYMUS L. WILD RYE, LTME GRASS 



Spikelets 2-6-flowered (uppermost florets imperfect), in pairs (sometimes soli- 

 tary below, rarely in 3's or 4's), sessile at the alternate notches of the continuous 

 rhachis; rhachilla articulated above the glumes and between the florets ; glumes 

 equal, rigid, narrow, 1-3-nerved, acute or awn-pointed, placed edge to edge in 

 front or toward the sides of the florets (which are dorso-ventral to the rhachis of 

 the spike) simulating an involucre at each joint of the rhachis ; lemmas convex, 

 obscurely 5-nerved, obtuse, acute or awned from the apex ; paleas a little 

 shorter than their lemmas ; grain hairy at the summit, adherent to the lemma 

 and palea. Erect tufted perennials with flat leaves and closely flowered 

 terminal spikes. (Name from tXtieiv, to roll up, an ancient one for some 

 grain.) 



Glumes as long as the florets or nearly so. 

 Lemmas awned. 

 Spikelets spreading. 

 Glumes awl-shaped .......... 6. E. striatut. 



Glumes narrowly lanceolate. 



Glumes indurated below ; spike erect. 



Awn long and spreading 2. E. an-xtralig. 



Awn short and erect 1. E. virginicut. 



Glumes not indurated below ; spike noddii . 



Spike large and densely flowered throughout . . . 4. E. robust us. 



Spike more slender and less densely flowered, interrupted 

 below. 



Lemma hirsute . . 8. E. canadensit. 



Lemma minutely scabrous 5. E. briicfiytacAys. 



Spikelets appressed to rhachis. 



Spikelets in pairs 8. E. glau-cti*. 



Spikelets mostly solitary ......... 7. E. Mtieounii. 



Lemmas awnless . . . . . 9. E. artntiriiis, 



Glumes reduced U* short awns ......... 10. E. dicertiglitmit. 



