104 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM, 
69. PUCCINELLIA Parl. Mrapow arass. 
Cespitose perennial with flat leaves and narrow terminal panicles; spikelets as in 
Panicularia but with usually smaller lemmas, the nerves less distinct or obscure. 
1. Puccinellia airoides (Nutt.) Wats. & Coult. in A. Gray, Man. ed. 6. 668. 1890. 
Poa airoides Nutt. Gen. Pl. 1: 68. 1818. 
Panicularia distans airoides Scribn. Mem, Torrey Club 5: 54. 1894. 
Type tocauity: “‘In depressed situations around the Mandan village, on the 
Missouri.”’ 
Ranar: British America to Nevada and New Mexico. 
New Mexico: Shiprock; Farmington; Arroyo Pecos near Las Vegas. Wet ground, 
in the Upper Sonoran Zone. 
70. AGROPYRON Gaertn. WHEAT GRASS. 
Tall perennials with erect simple culms and often bearded terminal spikes; spike- 
lets 3 to many-flowered, closely sessile and single at each notch of the axis; rachilla 
articulated above the glumes under each lemma; glumes 2, narrower and usually 
shorter than the lemmas, acute or awned; lemmas rounded on the back or slightly 
keeled above, 5 to 7-nerved, acute or awned from the apex, rarely obtuse; palea 2- 
keeled, bristly-ciliate on the keels; grain pubescent at the apex, usually adherent to 
the palea. 
KEY TO THE SPECIES. 
Rachis of the spike breaking up at maturity, the joints falling 
with the spikelets................0.0020000 eee cece eee 1. A. seribneri. 
Rachis of the spike continuous, not breaking up at maturity. 
Awns of the lemmas conspicuous, 
Awns erect. 
Awns short, not exceeding the body of the lemma; 
spikes usually tinged with purple.......... 2. A. violaceum. 
Awns long, usually exceeding the body of the 
lemma; spikes not purplish tinged. 
Stems stout; spikes 7 to 10 mm. wide, usually 
unilateral; spikelets (excluding the awns) 
12 to 15 mm. long... ......22222....... 3. A. richardsoni. 
Stems slender; spikes about 5 mm. wide, seldom 
unilateral; spikelets (excluding the awns) 
about 10 mm. long. .... 222.222.202.222. 4. A. caninum. 
Awns divergent. 
Spikelets subterete, more or less crowded.......... 5. A. bakeri. 
Spikelets flattened, distant. 
Leaves scabrous above. ..........2.2.-....2-. 6. A. arizonicum. 
Leaves glabrous. .............0222.-0.0222.-. 7. A, spicatum. 
Awns of the lemmas not conspicuous. 
Plants bright green, not glaucous. 
Plants cespitose; spikelets small, few-flowered. .... 8. A. tenerum. 
Plants stoloniferous; spikelets large, many-flowered. 9. A. pseudorepens. 
Plants conspicuously glaucous. 
Sheaths pubescent... ...........0.cc0ee cece eaeee 10. A. palmert. 
Sheaths glabrous. 
Lemmas scabrous or glabrous. ................ 11. A. smithii. 
Lemmas pubescent.................-- Leeeeeee 12. A. molle, 
