WOOTON AND STANDLEY- — FLORA OF NEW MEXICO. 99 



Panicles open, broad, on long or short pe- 

 duncles. 

 Panicles very short, 5 cm. or less; 

 plants less than 30 cm. high; 

 leaves smooth beneath, scabrous 



above 15. P. brevipaniculata. 



Panicles longer, 8 to 15 cm.; plants 30 

 to 60 cm. high; leaves variously 

 pubescent. 

 Glumes nearly equal, 3-nerved; 

 leaves smooth beneath, sca- 

 brous above 16. P. arida. 



Glumes unequal, the first 1-nerved, 

 the second 3-nerved; leaves 

 scabrous beneath, hispid- 



puberulent above 17. P . fendleriana. 



Cobweb present at the base of the flowers, though some- 

 times scanty; lemmas acute (except in P. com- 

 pressa) and usually strongly keeled; plants with 

 horizontal rootstocks; spikelets and lemmas 

 various. 

 Intermediate nerves of the lemmas faint or obsolete. 



Stems compressed; panicles narrow, open 8. P. compressa. 



Stems not compressed; panicles various. 



Branches of the panicles reflexed 9. P. aperta. 



Branches of the panicles not reflexed 10. P. interior. 



Intermediate nerves of the lemmas conspicuous. 

 Panicles with numerous many-flowered spikelets, 

 the branches in fruit ascending (the lower 



ones in 3's and 4's); lemmas acutish 3. P. pratensis. 



Panicles usually with few-flowered spikelets, the 

 • branches reflexed or spreading in fruit; 



lemmas very acute. 

 Spikelets few, usually purplish; branches of 

 the panicle few, solitary or in pairs. 

 Intermediate nerves of the lemmas 



long-hairy 4. P. arctica. 



Intermediate nerves of the lemmas gla- 

 brous, the hairs on the principal 



nerves copious and spi'eading 5. P. rejlexa. 



Spikelets numerous, green; branches of the 

 panicle numerous, the lower ones 

 often in 3's and 4's. 

 Lemmas only slightly pubescent on the 



keel below 6. P. occidentalis. 



Lemmas copiously white-pubescent on 

 the back below, villous on the 

 marginal nerves and keel 7. P. tracyi. 



1. Poa annua L. Sp. PI. 68. 1753. Low speargeass. 



Type locality: "Habitat in Europa ad vias." 



Range: Nearly throughout the United States; also in Europe and Asia. 



New Mexico: Santa Fe; Ponchuelo Creek. Moist soil, in the Upper Sonoran and 

 Transition zones. 



