158 



Paniceae 



Panicum 



o 5o 



Map 278 



Panicum virgatum L. 



53 



Map 280 



Panicum stipitatum Nash 



to Panicum Gattingeri until satisfactory characters are found to separate 

 them. 



N. Y., Ont. to Minn., southw. to N. C. and Tenn. 



3. VIRGATA 



Perennials from stout rootstocks; spikelets gaping at the apex, owing 

 to the well developed staminate floret and its palea in addition to the 

 perfect one; species mostly maritime, only one in Indiana. 



6. Panicum virgatum L. (Linder. Some varieties of Panicum virgatum. 

 Rhodora 24: 11-16. 1922.) Switchgrass. Map 278. This species is found 

 as a native in almost all the counties in the state and is now introduced 

 in sand ballast along railroads in many counties. It is not a native of 

 Wells County but I have found it along railroads in three widely separated 

 places in the county. It prefers the open and a sandy soil. Where it is 

 found, it is generally common over the extent of its habitat. It is found 

 in sandy prairies, "oak openings," on gravelly banks of lakes and streams, 

 and along the Ohio River it often grows among the cobblestones of boat 

 landings and in the seams of outcrops of shale. 



Maine, Que. to Mont., southw. to Fla., Nev., and Ariz.; Mex. and 

 Cent. Amer. 



4. AGROSTOIDIA 



Tufted perennials; culms erect, compressed; sheaths keeled; ligules 

 membranous, 0.5-1 mm long; spikelets short-pediceled, lanceolate, pointed, 

 glabrous, 5-7-nerved; fruit smooth and shining, with a minute tuft of 

 stout hairs at the apex. 



Rootstocks present; blades pilose above toward the base; spikelets 3-3.8 mm long 



7. P. anceps. 



Rootstocks lacking; blades not pilose above toward the base; spikelets less than 3 mm 

 long. 

 Spikelets 2.4-2.8 mm long, conspicuously secund; fruit with a basal stalk 0.2-0.4 mm 

 l on g 8. P. stipitatum. 



