138 



POACEAE 



1. Muhlenbergia microsperma (DC.) Kunth. 

 Annual Muhlenbergia. Fig. 298. 



Trichochloa microsperma DC. Cat. Hort. Monsp. 151. 1813. 

 Podosaemum dcbile H. B. K. Nov. Gen. & Sp. 1 : 128. 1816. 

 Muhlenbergia debilis Kunth, Rev. Gram. 1: 63. 1829. 

 Muhlenbergia microsperma Kunth, Rev. Gram. 1: 64. 1829. 

 Muhlenbergia purpurea Nutt. Journ. Acad. Phila. II. 1: 186. 

 1848. 



Annual, often purple ; culms spreading, 15-35 

 cm. tall, scaberulous, especially below the nodes; 

 sheaths smooth or scaberulous ; ligule 1 mm. long ; 

 blades 2.5-5 cm. long, 1 mm. wide, flat, scabrous ; 

 panicles narrow, loose, 2-7 cm. long; glumes ovate, 

 obtuse or emarginate, 1-nerved, uneciual. the second 

 the longer, 1 mm. long; lemma narrow, acuminate, 

 3-nerved, 3 mm. long, appressed-pubescent on 

 margins and callus ; awn terminal, capillary, 10-14 

 mm. long. Cleistogamous spikelets are developed 

 at the base of the lower sheaths. These are soli- 

 tary or few in a fascicle in each axil, each spikelet 

 included in an indurate thickened, tightly rolled nar- 

 rowly conical reduced sheath; which readily dis- 

 articulates from the plant at maturity. The glumes 

 are wanting and awn of the lemma reduced, but the 

 grain is larger than that of the spikelets in the 

 terminal inflorescence, being about the same length 

 (2 mm.) but much thicker. 



Open ground, Lower Sonoran Zone. Mar. -May. Type 

 locality: Mexico. 



2. Muhlenbergia andina (Nutt.) Hitchc. 



Hairy Muhlenbergia. Fig. 290. 



1848. 



Calamagrostis andina Nutt. Journ. Acad. Phila. II. 1: 187. 

 Vaseya comata Thurb. Proc. Acad. Phila. 1863: 79. 1863. 

 Muhlenbergia comata Thurb.; Benth. Journ. Linn. Soc. Bot. 19: 83. 



1881. 

 Muhlenbergia andina Hitchc. U. S. Dept. Agr. Bull. 772: 145. 1920. 



Perennial, with numerous scaly rhizomes ; culms erect 

 or sometimes spreading, smooth below, scabrous above, 

 pubescent about the nodes, 50-100 cm. tall; sheaths smooth 

 or slightly scabrous, keeled ; ligule 1 mm. long, membrana- 

 ceous, short-ciliate ; blades flat, 2-6 mm. wide, scabrous ; 

 panicles narrow, spikelike, usually more or less lobed or 

 interrupted, often purple-tinged, 7-15 cm. long; glumes 

 narrow, acuminate, 1-nerved, smooth, ciliate-scabrous on 

 the keels, 3-4 mm. long; lemma 3 mm. long, gradually 

 narrowed into a capillary awn 4-8 mm. long, the hairs 

 at base of floret copious, 2-3 mm. long. 



Open ground, Arid Transition Zone; Cascade and Sierra Nevada Mountains from Washington to Cali- 

 fornia, east to Wyoming. July-Aug. Type locality: "LTpper California on the Colorado of the West." 



3. Muhlenbergia squarrosa (Trin. ) Rydb. 

 Short-leaved Muhlenbergia. Fig. 300. 



Vilfa squarrosa Trin. Mem. Acad. St. Petersb. VI. Sci. Xat. 4': 100. 



1840. 

 I'ilfa richardsonis Trin. Mem. Acad. St. Petersb. \ I. Sci. Nat. 4': 



103. 1840. 

 Vilfa depauperata Torr. ; Hook. Fl. Bor. Am. 2: 257. pi. 2?6. 1840. 



not Muhlenbergia depauperata Scribn. 

 Sporobolus depauperatus Scribn. Bull. Torrey Club 9: 103. 1882. 

 Sporobolus richardsonis Merr. Rhodora 4: 46. 1902. 

 Muhlenbergia squarrosa Rydb. Bull. Torrey Club 36: 531. 1909. 



Perennial from numerous hard creeping _ rhizomes ; 

 culms wiry, erect or decumbent at base, from 5 cm. to as 

 much as 60 cm. in height; blades flat or usually involute, 

 1-5 cm. long; panicle narrow, interrupted, or sometimes 

 rather close and spikelike. 2-15 cm. long; glumes ovate, 

 1 mm. long; lemma lanceolate, acute, mucronate, 2 mm. 

 long. 



Dry or moist open ground, L'pper Sonoran and Arid Transition 

 Zones; eastern Washington to California, east to Montana and south 

 to central Mexico. June-Aug. Type locality: Menzies Island, Co- 

 lumbia River. 



