96 POACEAE 



awned at the apex, keeled to the base. Grain slightly compressed laterally, 

 deeply furrowed, free, pubescent at the apex. 



1. S. cereale L. Annual or biennial; stem 1.5-3 m. high, glabrous; leaves 

 scabrous, flat; spike 10-15 cm. long, 4-angled; spikelets 2-flowered; empty glumes 

 subulate; lemma lanceolate, hispid ulous-ciliate, 5-nerved, awned. Waste 

 places and old fields: escaped from cultivation. 



75. HORDEUM L. BARLEY, SQUIRREL-TAIL, FOXTAIL. 



Annuals or rarely perennials, with spicate inflorescence. Spikelets alter- 

 nately in 3's, rarely in 2's, at each node of the articulate rachis, sessile or short- 

 pediceled, 1-flowered; flower perfect or in the lateral spikelets often imperfect 

 or rudimentary; rachilla extending beyond the flower as a long slender bristle. 

 Empty glumes 2, awnlike, subulate, or lanceolate, rigid, falling together with the 

 rachilla-joint. Lemma lanceolate, rounded on the back, awned, lobed, or in 

 the lateral spikelets awnless. Palet shorter, 2-keeled. Styles very short, dis- 

 tinct; stigmas plumose. 



Lateral spikelets sessile; annuals. 



Lemma not awned, the awns represented by chartaceous lobes. 1 . H . aegiceras. 



Lemma awned. 2. H. rulgare. 



Lateral spikelets stalked; lemma awned. 

 Floret of the central spikelet sessile. 



Empty glumes of the central spikelets lanceolate. 3. H. pusillum. 



Empty glumes of central spikelet not lanceolate. 



Inner empty glumes of the lateral spikelets broadened. 4. H. maritimum. 



Empty glumes all setaceous. 

 Lateral floret not awned. 



Plant low, 5-25 cm. high; upper sheaths inflated. 5. H. depressum. 

 Plant taller, 2-0 dm. high; upper sheath not conspicuously inflated. 

 Lateral floret neutral or staminate; lemma of the central floret 6-8 



mm. long. . 6. H. nodosum. 



Lateral floret usually perfect; lemma of the central flower 10 mm. 



long. 7. //. boreale. 



Lateral florets long-awned. 



Awn 2-3 cm. long. 8. //. caespitosum. 



Awn 4-6 cm. long. 9. H. jubotum. 



Floret of the central spikelets stalked. 



Empty glumes not ciliate. 10. H. montanense. 



Empty glumes or some of them ciliate. 11. H. murinum. 



1. H. aegiceras (E. Mey.) Royle. Stem 5-7 dm. high; leaf-blades glabrous, 

 1-1.5 cm. broad; spikes about 1 dm. long; spikelets all fertile; empty glumes 

 lance-subulate, strigose; lemma 3-lobed at the apex; lateral lobes lanceolate, 

 acute, divergent; middle lobe ovate, obtuse, slightly hooded. PEARL BARLEY. 

 Moist waste grounds: cult, and often escaped. Plain Submont. 



2. H. vulgare L. Annual or rarely biennial; stem 5-7 dm. high; leaf-blades 

 broad, flat; ligules obsolete; spikes about 1 dm. long; empty glumes small, sub- 

 ulate, awned; spikelets all hermaphrodite; lemma lanceolate, long-awned, smooth. 

 BARLEY. Waste places and old fields: sometimes escaped from cultivation. 



3. H. pusillum Nutt. Tufted annual; stem 1-4 dm. high, usually de- 

 cumbent at the base; leaf-blades 1-7 cm. long, 1-4 mm. wide; spike 3-7 cm. long; 

 central spikelets perfect, the lateral ones imperfect; inner empty glumes of the 

 lateral spikelets lanceolate, the outer ones subulate, all awned; lemma smooth, 

 that of the central spikelet 6-8 mm. long, short-awned, those of the lateral 

 spikelets smaller and stalked. Dry soil: Ont. Ga. Calif. B.C. Plain 

 Submont. Ap-Je. 



4. H. maritimum With. Annual or perennial, branched at the base; 

 branches decumbent below, then ascending, somewhat geniculate, 1-2 dm. high; 

 sheaths loose, pubescent; spike short-exserted or the base included, 3-5 cm. long; 

 empty glumes setaceous except the inner ones of the lateral spikelets, which are 

 sometimes staminate, distinctly awned; otherwise like H. nodosum. Saline soil: 

 Calif. Wash. Ida. Utah. My-Jl. 



6. H. depressum (Scribn. & Smith) Rydb. Tufted; stem 5-15 cm. high, 

 geniculate at the base, which is covered by the sheaths; leaf -blades 1-3 cm. long, 

 1-3 mm. wide, auricled at the base, finely pubescent; spikes 2-3 cm. long; lemma 



