GRASS FAMILY 27 



Empt> glumes less than one-fourth as long as the lemma; stem 

 diffuse, decumbent or creeping; plant not tufted. 



8. M. Schrebcri 

 Empty glumes one-tliird as long as the lemma or longer; stem 



erect or decumbent at the base only; plant tufted. 



9. A/. Richardsonis. 

 Plant annual ; rootstock, if any, -very slender. 



Lemma merelj awn-pointed, decidedly purplish; plant 1-2 dm. 

 high. 

 Spikelets 2 mm. long or more; inflorescence short and rather 



dense; stem 0.5-1 mm. thick. 10. M. simplex. 



Spikelets about 1.5 mm. long; inflorescence slender and lax; 

 stem very slender, filiform. 11. M. fllifonnis. 



Lemma with a distinct awn 0.5-1 mm. long, greenish; plant 

 4-6 cm. high. 12. M. aristata. 



Spikelets about 1 mm. long; plant less than 4 cm. high, annual. 



13. M. Wolfii. 

 Lemma long-awned. 



Leaf-blades erect, glabrous or minutely scabrous ; stem and sheaths glabrous. 

 Lemma glabrous; rootstock short and woody. 14. M. pauciflora. 



Lemma pubescent on the lower half; rootstock slender, creeping, 

 branched. 15. M. polycaulis. 



Leaf-blades spreading, as well at the stem below the nodes and the sheaths 

 scabrous-puberulent ; lemma pubescent on the lower half; rootstock 

 creeping. 16. M. curtifolia. 



Second glume sharply 3-5-toothed; flowering glume long-awned; awn at least 

 one-half as long as the glume. 

 Stem 3-6 dm. high, leafy; panicle 7-12 cm. long; awn 8-15 mm. long. 



17. M. gracilis. 

 Stem 1-3 dm. high, almost naked above; panicle 3-7 cm. long; awn 1-4 mm. long. 



Spikelets 3^ mm. long; awn 2-4 mm.; leaf-blades usually stiff. 



18. M. subalpina. 

 Spikelets about 2 mm. long; awn 1-2 mm.; leaf-blades filiform. 



19. M. filiculmis. 

 Panicle open, its branches long and spreading. 



Plants densely cespitose, branched onlj at the bse. 



Secondary branches of the panicle single; bsal leaves short, strongly recurve 1. 



20. A/, gracillima. 

 Secondary branches of the panicle fascicled; basal leaves not recurved. 



21. M. pungens. 

 Plants diffusely branched, prostrate. 22. M. Porteri. 



22. LYCURUS H.B.K. Texas Timothy. l. L. phleoides. 



23. PHLEUM L. Timothy. 



Spikes usually elongated-cylindric ; awns less than one-half the length of the outer glumes. 



1. P. pratense. 

 Spikes short, ovoid or oblong; awns about one-half the length of the outer glumes. 



2. P. alpinum. 



24. ALOPECURUS L. Foxtail. 



Awn about twice as long as the lemma. 



Spikes 8-12 mm. thick; empty glumes 3.5-4.5 mm. long, abruptly acuminate. 



1. A. occidentalis. 

 Spike about 5 mm. thick; empty glumes about 3 mm. long, obtuse. 



Stem erect, 3-5 dm. high, slightly if at all geniculate at the base, pale: ligules 



4-5 mm. long, acutish. 2. A. pallescens. 

 Stem decumbent, and geniculate at the base, 1-1.5 dm. high; ligules 2 mm. long, 



obtuse. 3. A. Macounii. 

 Awn scarcely exceeding the lemma. 



Stem erect, 1.5-5 dm. high; spike cylindric, obtuse. 4. A. aristulatus. 



Stem geniculate at the base, 1-5 cm. high; spike oblong, acute. 5. A. caespitosus. 



25. PHIPPSIA R. Br. 1. P. algida. 



26. BLEPHARONEURON Nash. i. B. tricholepis . 



27. SPOROBOLUS R. Br. Drop-seed, Rush-grass. 

 Perennials. 



First glume one-half as long as the second or less; plants not with long, scaly roos- 

 stocks. 

 Branches of the panicle verticillate. 1. S. argutus. 



Branches of the panicle scattered. 



Spikelets about 2 mm. long; first glume lanceolate. 



Sheath naked or sparingly ciliate at the throat; empty glumes glabrous. 

 Plant 3 dm. liigh or less; spikelets long-pedicelled; sheaths sparingly 



villous. 9. S. texanus. 



Plant 5-10 dm. high; spikelets short-pedicelled ; sheaths glabrous. 



2. S. airoides. 

 Sheath with a conspicuous tuft of hairs at the throat; empty glumes scab- 

 rous on the keel. 



Leaf-blades widely spreading, involute; sheath pubescent with long 

 hairs, at least towards the base. 3. S. Nealleyi. 



