GRAMINEAE 35 



Nat. from Eu. — Pennsylvania : Northampton ; Philadei,phia ; Lan- 

 caster ; Franki,in ; Chester ; Ai,legheny ; Erie. 



55. POA h. 



Annuals or biennials : stems densely tufted, low, usually less than 3 dm. long. 



1. P. annua. 

 Perennials : stems usually exceeding 3 dm. tall. 

 Plants green with no long rootstocks. 

 Flowering scales with the nerves glabrous. 2. P. debilis. 



Flowering scales with one or more of the nerves pubescent. 

 Flowering scales with long crimped hairs at the base. 

 Flowering scales with only the midnerve pubescent. 

 Flowering scales 2.5 mm. long, the midnerve sparsely pubescent : 



plant yellowish green. 3. P. trivialis. 



Flowering scales 3.5 mm. long, the midnerve densely pubescent: 

 plant green. 4. P. alsodes. 



Flowering scales with the midnerve and lateral nerves pubescent. 

 Midnerve of the flowering scale pubescent only below the middle. 

 Flowering scales 2-3 mm. long: basal leaves usually relatively 

 short. 

 Intermediate nerves of the flowering scales obscure. 



5. P. serotina. 

 Intermediate nerves of the flowering scales prominent. 



6. P. pratensis. 

 Flowering scales 4-5 mm. long : basal leaves very long, often equal- 

 ling the stem or nearly so. 7. P. brevifolia. 



Midnerve of the flowering scale pubescent the whole length, or nearly 

 so. 8. P. sylvestris. 



Flowering scales with no crimped hairs at the base. 9. P. aulumnalis. 

 Plants dull bluish green, with long stout often branching rootstocks : stems 

 much compressed. 10. P. compressa. 



1. Poa annua I/. Annual Meadow Grass. Low Spear-grass. 

 (Man. p. 138 ; I. V.f. 459.) In waste and cult, places nearly throughout 

 N. Am. Nat. from Eu. — Pennsylvania : Delaware ; Chester. ; Bucks ; 

 Luzerne ; Northampton ; Lancaster ; Huntingdon ; Blair; Erie 

 Ali<egheny ; Philadelphia ; Monroe ; Somerset. Common. 



2. Poa debilis Torr. Weak Spear-grass. (Man. p. 139 ; I. F.y. 

 472.) In woods, N. S. and N. B. to Minn., R. J., Pa. and Wis. Penn- 

 sylvania: Monroe, Naomi Pines. 



3. Poa tiivialis L. Roughish Meadow Grass. (Man. p. 139 j 

 I. F.y! 468.) In meadows and waste places, N. B. to Mich, and Va. 

 Nat. from Eu. — Pennsylvania : DELAWARE ; CHESTER ; Bucks ; Phila- 

 delphia ; Northampton ; Lancaster ; Centre ; Clinton ; Somer- 

 set ; Pike ; Allegheny. 



4. Poa alsodes A. Gray. GrovE MEAdow-grass. (Man. p. 140 ; 

 I. F.y! 475.) In woods and thickets, N. S. to Minn., N. C. and Tenn.— 

 Pennsylvania : Sullivan, on Loyalsock ; Erie ; Somerset. 



5. Poa serotina Ehrh. False Red-Top. Fowl Meadow-grass. 

 (Man. p. 139; I. F.y! 47J^.) In swampy places, N. S. and N. B., to Van- 



