26 POACEAE. 



Second glume not toothed or slightly so ; flowering glume awnless or rarely 

 very short-awned. 

 Empty glumes more than half as long as the flowering glume, acuminate. 

 Flowering glumes scabrous, green or dark. 



Panicle dense, obtuse, 5-10 mm. wide. 4. M. Wrightii. 



Panicle slender and lax, attenuate at the apex, less than 5 mm. wide. 



5. M. cuspidata. 

 Flowering glumes more or less purplish, sparingly long-hairy. 



6. M. Thurberi. 

 Empty glumes less than half as long as the flowering glume, obtuse or 



abruptly acute. 

 Spikelets (excluding the awn if present) 1.5 mm. or more long. 



Plant with a strong perennial, scaly root-stock. 7. M. Richardsonis. 

 Plant annual ; root-stock, if any, very slender. 



Flowering glumes merely 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. 8. M. simplex. 



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

 stem very slender, filiform. g. M, Uliformis. 



Flowering glumes with a distinct awn J^-i mm. long, greenish ; 

 plant 4-6 cm. high. 10: M. aristata. 



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



11. M. WoWi. 

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



least y^ as long as the glume. 

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



12. M. gracilis. 

 Stem 1-3 high, almost naked above ; panicle 5-7 cm. long ; awn 1-4 mm. 



long., 

 Spikelets 3-4 mm. long ; awn 2-4 mm. ; leaves usually stiif. 



13. M. subalpina. 

 Spikelets about 2 mm. long ; awn 1-2 mm. ; leaves filiform. 



14. M. Micuhnis. 

 Panicle open, its branches long and spreading. 



Plants densely cespitose, branched only at the base. 



Secondary branches of the panicle single ; basal leaves short, strongly re- 

 curved. 15. M. gracillima. 

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



16. M. pungens. 

 Plants diffusely branched, prostrate. 17. M. Porteri. 



1. Muhlenbergia mexicana (L.) Trin. In wet meadows and swamps from 

 N. B. to N. D., N. C. and Colo.— Alt. 4000-6500 ft.— New Windsor, Weld 

 Co. ; Rocky Ford ; Fort Collins ; gulch west of Soldier Cafion ; Tobe Mil- 

 ler's ranch, near La Porte. 



■z. Muhlenbergia racemosa (Michx.) B. S. P. (M. glomerata Trin.) In 

 wet meadows from Newf. to B. C, N. J., N. M. and Ore. — Alt. 4000-10,000 

 ft.— Colorado Springs; Cheyenne Mountain; Engelmann Canon; vicinity of 

 Ouray; New Windsor, Weld Co.; Estes Park, Larimer Co.; Fort Collins; 

 Black Caiion; Deer Run; Manitou; Middle Park. 



3. Muhlenbergia comata (Thurb.) Benth. In wet soil, especially in sand 

 from Mont, to Wash., Kans. and Calif. — Alt. 6500-10,000 ft. — Mountains near 

 Pagosa Peak; Gunnison; Carlton Lake, Grand Co.; Georgetown; Gypsum 

 Creek Canon, Eagle Co. ; Twin Lakes ; Hinsdale Co. ; Empire. 



4. Muhlenbergia Wrightii Vasey. In wet places in the mountains of Colo., 



