MANUAL OF THE GRASSES OF THE UNITED STATES 141 



Plants delicate, mostly less than 25 cm tall; blades 

 mostly not more than 2 mm wide (see also 

 E. frankii var. brevipes). 

 Panicle lax, the branches usually naked at base; 

 spikelets 4 to 7 mm long. 



19. E. TEPHROSAXTHOS. 



Panicle rather stiff, the branches often floriferous 

 nearly to the base; spikelets mostly not more 



than 3 mm long 20. E. peregrina. 



lb. Plants perennial. 



9a. Panicle elongate, slender, dense, spikelike 6. E. spicata. 



9b. Panicle open or contracted, not spikelike. 



10a. Plants with stout scaly rhizomes 1. E. obtusiflora. 



10b. Plants without rhizomes. 



11a. Spikelets subsessile or nearly so, the lateral pedicels not more than 

 1 mm long- 

 Spikelets subsessile, distant along the few stout panicle branches 



2. E. SESSILLSPICA. 



Spikelets short-pediceled. 



Panicle large, becoming a tumble weed, the axis and branches viscid. 



3. E. < URTIPEDICELLATA. 



Panicle narrow (rarely open in E. secundiflora) , not a tumble weed 

 nor viscid; keels of palea forming a thick white band. 

 Lemmas 3 mm long, somewhat abruptly narrowed to the acute 

 apex; panicle usually red-brown; anthers 0.2 to 0.3 mm long. 



4. E. SECUNDIFLORA. 



Lemmas 3.5 mm long, tapering to the acuminate apex; panicle pale 

 or slightly pinkish; anthers 0.4 to 0.5 mm long. 



5. E. BEYRICHII. 



lib. Spikelets with pedicels more than 1 mm long (appressed along the 

 branches in E. refracta; sometimes scarcely more than 1 mm long in 

 E. chariis and E. bahiensis). Panicles large and open (sometimes 

 condensed in E. bahiensis) . 

 12a. Nerves of lemma obscure; lemma rounded on back, sometimes 

 slightly keeled toward apex. 

 Axils of main panicle branches usually strongly pilose (rarely glabrous 

 in E. intermedia). 

 Sheaths pilose or hirsute. 



Culms mostly more than 50 cm tall; blades elongate, flat, not 



crowded at base of culm 30. E. hirsuta. 



Culms mostly less than 50 cm tall; blades rather short and 



crowded at base of culm 32. E. trichocolea. 



Sheaths glabrous or nearly so, except the pilose summit. 



Spikelets about 1 mm wide, 3- to 7-flowered, 3 to 5 mm long; 



lemmas 1.3 to 1.5 mm long 31. E. lugexs. 



Spikelets about 1.5 mm wide; 3- to 8-flowered, 3 to 10 mm long; 



lemmas 1.8 to 2 mm long 35. E. ixteemedia. 



Axils of main panicle branches glabrous or the lower sparsely pilose. 

 Pedicels bearing above the middle a glandular band or spot; axils 



glabrous 36. E. swallexl 



Pedicels without glandular band; lower axils sparsely pilose to 

 glabrous. 



Lemmas about 3 mm long 33. E. erosa. 



Lemmas about 2 mm long 34. E. palmeri. 



12b. Nerves of lemma evident, usually prominent; lemmas keeled. 

 Spikelets approximate in a somewhat condensed panicle, or along the 

 main branches of a somewhat spreading panicle; florets mostlv 

 15 to 30. 



Paleas readily deciduous 45. E. chariis. 



Paleas persistent 46. E. bahiensis. 



Spikelets in an open panicle. 



Panicle longer than broad, the branches not horizontally spreading. 

 Culms not more than 60 cm tall. 



Spikelets 9- to 15-flowered; panicle less than one-third the entire 



length of culm, the branches Dot viscid 37. E. tracyi. 



Spikelets 4- to 8-flowered; panicle more than half the entire 

 length of culm, the branches viscid 3S. E. silveana. 



