72 FLORA OF THE YELLOWSTONE NATIONAL PARK. 



Poa tenuifolia, Buckl. 



Everywhere over the lower dry areas, one of the principal "bunch 

 grasses," and frequent on subalpine slopes (632, 637). 



Foa alpina, L. 



From 6500 ft. alt. to alpine. At low elevations in cool, moist situa- 

 tions (627, 628). 



Poa Pringlei, Scribn. 



In dense tufts in compact dry soil on exposed rocky lidges from 8000- 

 9500 ft. alt. (633). 



Poa cuspidata, Vasey, ined. 



Dry meadows along Slough Creek, 6500 ft. alt. (636). 



Poa Patterson!, Vasey, ined. 



On slides and in crevices of rocks. Soda Butte Creek, 8500 ft. alt. 

 (634). 



Poa reflexa, V. and S. 



Alpine slopes (274 and 638 in part). 



Poa acuminata, Scribn., n. sp. 



Common in cold meadows and bogs, and less so on alpine and sub- 

 alpine slopes from 7000-10,000 ft. alt. (639). 



Poa laevis, Vasey, ined. 



Sandy bluffs at outlet of Yellowstone Lake, 7800 ft. alt. (643). 



Poa Nevadensis, Vasey. 



A characteristic species of moist meadows and bogs from 7500-9000 

 ft. alt. The glaucous form more frequent in bogs (276, 642, 645). 



Poa nemoralis, L. 



Kather dry meadows and banks from 7000 9000 ft. alt. (275, 640, 647). 



Poa pratensis, L. 



Meadows and bogs from 5500-8500 ft. alt. Common at low elevations 

 (254, 646). 



Poa Vaseyana, Scribn., ined. 



"Wet places at low elevations. Not common (C44). 



Glyceria airoides, Thurb. 



Frequent on hot spring and geyser formation (271, 595) . 



Glyceria nervata, Trin. 



Rather rare along shaded watercourses. Miller Creek, 7200 ft. alt. 

 (593;; East Pelican Creek, 8500 ft. alt. Shoshone Lake (Coulter). 



