TRIANDRIA D1GTNIA 65 



long as the florets. Florets both sessile, pilose at base. Lotcer palea with an atvn 

 aear the base, which is somewhat geniculate in the middle, and one third to o'le 

 half longer than the palea. 



Hab. Dry, rocky banks : R. Strodc's : not common. Fl. June. Fr. July. 



Obs. I think this species is very rare, here : and my Chester County specimens, 

 although sanctioned by high authority, do not compare well with the undoubted 

 plant. They look loo much like the following species. 



2. A. cespitosa, L. Leaves flat, scabrous ; panicle finally diffuse, 

 pyramidal ; branches scabrous ; awns straight, about as long as the pa- 

 le®. Beck, Bot. p. 402. Specim. Gray, Gram. 2. no. 115. 

 A. ambigua? Mx. Am. 1. p. 61. Also] Pers. Syn. 1. p. 77. 

 Also] A. aristulata. Tow. FL 1. p. 132. Ejusd. Comp.p.64. Eat. 

 Man. p. 10. 

 Cespitose Aira. 



Root perennial. Culm 2 to 3 feet high, cespitose or growing in tussocks, glab- 

 rous. Leaves narrow, Linear, acute, nerved and scabrous on the upper surface, 

 smooth beneath : sheaths smooth : ligulc elongated, acuminate. Panicle capillary, 

 oblong, at fust contracted, finally diffuse; branches semi-verticiUate, acutel) 

 ■scabrous. Glumes generally of a bluish color, rather obtuse, shorter than the 

 florets. Florets pilose at base : the upper one on a hairy pedicel. Lower palea 

 with a scabrous awn near the base, which is straight, and scarcely as long as the 

 palea. 



flab. Moist places on the Serpentine rock: abundant. Fl. May. Fr. July. 



Obs. These Airas are dry, wiry grasses, of little or no value to the agriculturist. 

 Two or three additional species are enumerated in the U. States. 



42. KOELERIA. Pers. Mat. Gen. 104. 

 [Named in honor of M. Kocler, a German Botanist.] 



Spikelets compressed, 2 or 3-flowered. Glumes 2, shorter than the 

 florets, unequal, the lower one much narrower. Upper floret pedi- 

 cellate, with a short, awn-like rudiment, at the base of the upper palea. 

 Lower palea awnless, or sometimes awned. 



1. K. pennsylvanica, DC. Panicle long, very slender, rather loose; 

 spikelets shining, the terminal ones 3-flowered. Beck, Bot. p. 407. 



Aira melicoides 7 Mr. Am. I. p. 62. Pers. Syn. I. p. 77, Pursh* 



Am. 1. p. 76. 



A. mollis. Muhl Catal. p. 11. Ejusd. Gram. p. 82. JWitt. Gen. 1. 



p. 62. Ell? Sh. 1. />. 154. 



Also? A. triflora. Ell. Sh. 1. p. 153. 



A. pallcns. Florul. Cestr. p. 11. Not of Muhl. 



Pennsylvania* Koeleria. 



Root perennial, fibrous. Culm 2 to 3 feet high, smooth. Leaves short, lanceo- 

 late, flat, membranaceous ; lower ones softly pubescent, smooth, upper ones scab- 

 rous : sheaths glabrous, or pubescent ; little lacerate. Panicle 4 to 6 or 8 inche* 

 long, very slender, sometimes almost filiform, branches rather loose ; spikelets nor 

 crowded, generally 2-flowered, a little compressed, and of a pale yellowish green 

 color. Lower glume narrow, linear, acute ; upper one oblanceolate, 3-norved, olj- 

 ftse, or obscurely pointed. Upper floret pedicellate; the terminal spikeiet ms0B 



