jvate-oblong, usually 6- to 8-flowered; glumes broad, obtuse, much shorter than 

 the lower lemmas, often nerveless, the first glume about 1 mm. long, the second 

 nearly 2 mm. long; lemmas firm, 2-2.5 mm. long, obovoid, obtuse or acutish, 

 prominently 7-nerved, the apex distinctly scarious; stamens 2; palea apex with a 

 narrow slit. 



In wet meadows, swampy woods or along streams, in N.M. (Lincoln Co.) and 

 Ariz. (Apache, Coconino, Graham, Cochise and Pima cos.); Mont, to B.C., s. 

 in mts. to N. M., Ariz, and Calif. 



6. Glyceria grandis Wats, ex Gray. American manna-grass. Fig. 82. 



Culms stout, 1-1.5 m. tall from a perennial base; leaf blades flat, 6-12 mm. 

 wide; panicle large, compound, 20—40 cm. long, somewhat nodding at tip; spike- 

 lets 4- to 7-flowered, 5-6 mm. long; glumes 1.5-2 mm. long; lemmas purplish, 

 2-2.5 mm. long; palea slightly longer than lemma. 



Marshes, stream banks, wet meadows, and in mud and shallow water of ponds, 

 lakes and slow-flowing streams, in N. M. (Colfax, San Miguel and Taos cos.) 

 and Ariz. (Apache and Graham cos.); P.E.I, to Alas., s. to Va., Tenn., la.. Neb., 

 N.M., Ariz, and Ore. 



7. Glyceria pauciflora Presl. Weak manna-grass. Fig. 83. 



Culms 3-12 dm. tall, from a decumbent rooting base; sheaths smooth or 

 minutely scabrous, free and overlapping; blades thin, flat, lax, minutely scabrous, 

 mostly 8-20 cm. long, 5-15 mm. wide; panicle oblong or pyramidal, open or 

 rather dense and spikelike, nodding, 8-20 (or -25) cm. long, the branches ascend- 

 ing or spreading, rather flexuous, naked below, the spikelets crowded on the 

 upper half; spikelets 4- to 7-flowered (usually 5~ or 6-flowered), 4—6 mm. long; 

 glumes broadly ovate or oval, purplish-tinged, the first glume 1-1.5 mm. long, 

 the second glume 1.5-2 mm. long, 3-nerved, the nerves sometimes obscure, the 

 margins erose-scarious; lemmas oblong, 2-3 mm. (usually 2.5 mm.) long, with 

 5 prominent nerves and an outer short faint pair near the margins, minutely 

 scabrous on the nerves and somewhat so between ifiim, the tip rounded, scarious, 

 somewhat erose, usually with a purplish band below the scarious tip; caryopsis 

 with a sub-basal and oblong hilum. Torreyochloa pauciflora (Presl) Church, 

 Puccinellia pauciflora (Presl) Munz. 



Marshes, shallow water, and wet meadows, in N.M. (Sandoval and Taos cos.); 

 Alas, to S.D., N.M. and Calif. 



6. Poa L. Bluegrass 



Inflorescence paniculate; spikelets 2- to several-flowered, laterally compressed, 

 all the flowers functional except usually the terminal one reduced, in some species 

 the flowers unisexual and in some the male and female flowers on separate plants 

 (at least in some populations); rachilla abscising above the glumes and at the lower 

 part of each node; glumes usually shorter than first lemma, thin (marginally often 

 hyaline), keeled, the first usually 1-nerved, the second 3-nerved; lemmas keeled, 

 ovate-lanceolate, awnless, thin (marginally often hyaline), 5-nerved (or often 

 appearing only 3-nerved, one pair of nerves being obscure). 



A genus of about 300 species in cool and temperate regions of the world. 



1. Rhizomes present, often very extensively developed (2) 



1. Rhizomes lacking although plants sometimes stoloniferous (8) 



2(1). Culms strongly flattened, 2-edged; plants strongly rhizomatous; lemmas 

 sparsely if at all webbed 1. P. compressa. 



2. Culms slightly if at all flattened, not 2-edged; plants often either only weakly 



rhizomatous or with strongly webbed lemmas (3) 



185 



