86 CiRAMINEAE 



shorter tliau the first lemma; lemmas aimless or with a straiglit (rarely bent) avvn. 

 terminal or from between the teeth of a bidentate apex. 

 Spilielets of two kinds in the same inllorescence, perfect and sterile; spikelets fasciculate in 



1-sided panicles 57. L.\m.irckia. 



Spikelets all alike in the same inflorescence. 



Plants dioecious; perennials with creeping rhizomes or stolons (a few species of Poa are 

 dioecious). 



Spikelets solitary, concealed in the axils of short crowded rigid leaves 



44. MONANTHOCHLOE. 



Spikelets in exserted panicles 54. Distichlis. 



Plants not dioecious. 



Eachilla or lenunas provideil with long hairs exceeding the glumes in length; tall reeds. 



Hairs on lemmas, the raehilla naked 4(). Arundo. 



Hairs on the raehilla only 47. Phr.\gmites. 



Bacbilla and lemmas naked or the hairs shorter than the glumes. 



Spikelets sessile, in short terminal spikes; lemmas 5-toothed; low annual 



45. Orcuttia. 

 Spikelets in racemes or in open or contracted panicles. 

 Lemmas 3-nerved. 



Lemmas pilose on the nerves, longer than the glumes; callus densely villous. 



48. Tridens. 

 Lemmas sometimes pubescent but not pilose on the nerves; callus not villous. 



Glumes equaling or exceeding the spikelet 49. Dissanthelium. 



Glumes shorter than the first floret .50. Eragrostis. 



Lemmas 5 to many-nerved. 



Spikelets nearly sessile in dense 1-sided clusters at the ends of the few panicle 



branches 56. Dactylis. 



Spikelets not in dense 1-sided clusters. 



Lemmas flabelliform. many-nerved, petal-like 51. ANTHOciiLnA. 



Lemmas not flabelliform. 



Palea appendaged on the keels; inflorescence a simple raceme 



53. Pleuropogon. 

 Palea not appendaged. 



Spikelets very broad, much compressed, cordate; lemmas cordate 



55. Briza. 

 Spikelets not broad and cordate. 



Lemmas keeled, awnless (keeled in some species of Bromus but the 



bifid tip acuminate or awned) 58. PoA. 



Lemmas convex or keeled only at summit. 



Glumes large, mendiranaceous or papery, scarious-margined ; upper 

 2 or 3 lemmas empty, convolute around each other. .52. Melica. 

 Glumes not scarious-margined; upper lemmas not empty and con- 

 volute around each other. 



Nerves of lemmas 5 to 9, parallel, prominent 59. Glvceria. 



Nerves of lemmas not prominent, or not equally so. 



Lemmas obtuse, awnless, scarcely nerved 60. Puccin'ellia. 



Lemmas acute or awned, or, if obtuse, awned between the teeth 

 of the bifid apex. 

 Lemmas entire, acute or awned from the apex (very narrow 



teeth in P. elmeri etc) 61. Pestuca. 



Lemmas bifid at apex (except B. brizaeforniis), the awn if 

 present from between the teeth 62. Bromus. 



Tribe IX. Hordeae. Spikelets 1 to several-flowered (the uppermost floret imperfect), sessile 

 on opposite sides of a flattened or channeled rachis forming a spike; glumes sometimes 

 small or wanting, sometimes placed in pairs in front of the spikelet; auricular appendages 

 borne at the top of the sheath on each side at base of blade. 

 Spikelets solitary at each joint of the rachis (occasionally double in Agropyron). 

 Spikelets placed edgewise to the rachis, the lateral ones with a single glume. 



■ Spikelets several-flowered 63. LoLiuM. 



Spikelets 1-flowered 64. Monbrma. 



