June, 1914.] The Panicujns of Ohio. 349 



30. Spikelet }/s inch or more long. 32. 



30. Spikelet less than J/g inch long. 31. 



31. Spikelet less than j^ in long. Panicum polynnthes. (1.5.) 



31. Spikelet more than yg inch long. Panicum commutatum. (2S). 



32. Leaf sheaths mostly pappilose-hispid; nodes glabrous or short 



pubescent. Panicun: clanJcslinum. (31). 



32. Leaf-sheaths glabrous or soft-pubescent. 33. 



33. Nodes glabrous. Panicum latifolium. (29). 



33. At least the lower nodes pubescent or bearded. 34. 



34. Lower surface of the leaf blade velvety-pubescent; leaf-sheaths 



hairy. Panicum bosrii molJe. (.30a). 



34. Lower surface of the leaf blade not velvety-pubescent. .35. 



35. Panicle narrow, its branches appressed, rarely a little spreading; 

 upper nodes at least, not bearded. Panicum xanthophysum. (26). 



35. Panicle open, its branches spreading; the nodes appressed-pubes- 

 cent. Panicum hoscii. (30). 



SPECIES DESCRIPTIONS. 



1 . Panicum agrostoides Spreng. Agrostis-like Panic-grass. 

 An erect, rather stout, glabrous, perennial, 1/4-33^ feet high; 

 sheathes loo.se; blades flat, >i-lK inches long, %-H inch wide; 

 inflorescence a panicle, ])urplish, oblong-ovate, 6-12 inches long, 

 stiffly ascending, parts of tne panicle denseh' flowered ; spikelets 

 crowded, a few hairs on the short pedicel; second empty glume and 

 lemma of the stamina te flower sul^-equal. Along shores. Erie 

 county. 



2. Panicum stipitatum Nash. Long Panic-grass. A branch- 

 ed perennial ."j-.'i feet high; leaf-blade 1 foot long, often purplish, 

 acuminate, and scabrous; inflorescence a pyramidal, purplish 

 panicle, 4-12 inches long, more open than in the proceeding 

 species; spikelets secuud, acuminate, crowded, second empty 

 glume and lemma of the staminate flower equal; the outer empt}- 

 glume about \ as long as the second; no hairs at the base of the 

 spikelet. North-eastern Ohio to Loraiti, Fairfield and Colum- 

 biana. 



o. Panicum virgatum L. Tall Smooth Panic-grass. A 

 tall tufted perennial from a creeping rootstock; 1-2/X feet tall, 

 glabrous. Leaves long-acuminate, flat, 1 foot long, yi-Yi inches 

 wide, narrowed toward the base, rough on the margin ; panicle 

 erect or spreading, (3-20 inches high and about as wide; spikelets 

 ovate, acuminate; ottter empty glume acuminate, half as long as 

 the spikelet, .3-.") ner\'ed; second empty glume longer than the 

 other glumes, .")-7 ner\-ed, and exceeding the fruit. Low ground, 

 salt marshes or prairies. Variable. General. 



4. Panicum dichotomiflorum Mx. Spreading Panic-grass. 

 A glabrous, branching annual, becoming decumbent and geni- 

 culate. Sheathes loose, glabrous and somewhat flattened; leaves 

 (5-20 inches long, M-^ inch wide, scabrous above or on the 

 margin; panicle diffuse 4-16 inches long, spikelet crowded 1-8 itich 

 long; lanceolate, acute, glabrous, sometimes purplish; outer 

 empty glume % as long as the spikelet. General. 



