FLORA OF THE DISTRICT OF COLUMBIA. 87 



6. Eragrostis pilosa (L.) Beauv. 



Moist places; infrequent. Eastern states; introduced from Eur. 



7. Eragrostis caroliniana (Spreng.) Scribn. 



A common weed in open moist ground. Throughout the eastern and southern 

 U. S. (E. purshii Schrad.) 



8. Eragrostis minor Host. 



Open waste ground; rare; Beltsvillo; Anacostia. Late summer. Occasional at 

 scattered localities throughout the U. S.; introduced from Eur. (E. eragrostis Karst.) 



43. MELICA L. 



1. Melica mutica Walt. 

 Rocky woods; frequent above the fall line. Southern states, north to Pa. 



44. UNIOLA L. 



Panicle contracted, slender; spikelets 5-7 mm. long, narrow 1. 11. laxa. 



Panicle open, the branches drooping; spikelets 1.5-3 cm. long, broad and very flat. 



2. U. latifolia. 



1. Uniola laxa (L.) B. S. P. 



Moist woods; east of the fall line; infrequent. Summer. Southern states, north- 

 ward to Long Isl. ( U. gracilis Michx.) 



2. Uniola latifolia Michx. 



Rich woods; above the fall Line. Summer. Southern states, north to Pa. 

 A handsome grass, the drooping panicles of large, very flat spikelets being very 

 striking. 



45. DACTYLIS L. 



1. Dactylis glomerata L. Orchard grass. 



Cultivated as a meadow grass; frequently established in grassland and along road- 

 sides. May. Native of Eur. 



46. POA L. Bluegrass. 

 Plants annual. 



Florets not cottony at base; intermediate nerves of lemma distinct 1. P. annua. 



Florets with cottony hairs at base ; intermediate nerves indistinct. 2. P. chapmaniana. 

 Plants perennial. 



Creeping^rootstocks present. 

 Culms distinctly flattened; plants not tufted ; panicles contracted. 



3. P. compressa. 

 Culms terete or obscurely flattened; plants tufted; panicles open. 



Lower branches of the panicle usually in twos; basal leaves usually as long as 



the culm 4. P. cuspidata. 



Lower branches of the panicle usually in fives; basal leaves shorter than the 



culm 6- P- pratensis. 



Creeping rootstocks wanting. 



Lemma not cobwebby at base, conspicuously scarious at the rounded apex. 



6. P. autumnalis. 

 Lemma cobwebby at base. 

 Sheaths upwardly scabrous; marginal nerves of the lemma glabrous. 



7. P. trivialis. 

 Sheaths glabrous; marginal nerves of the lemma pubescent. 



Intermediate nerves of the lenuna faint; branches of the panicle ascending 



or spreading; lemma usually purple-tinged 8. P. palustris. 



Intermediate nerves of the lemma prominent; branches of the panicle finally 

 reflexed; lemma green 9. P. sylvestrls. 



