82 



GRASSES OF IOWA. 



Panicum lanuginosum is a variable species and can only be sep- 

 arated arbitrarily from P. unciphyllum. Perhaps we ought to regard 

 the two as one variable polymorphs species. 



DISTRIBUTION'. 



Iowa. Mt. Pleasant, 1916 (Mills); De Witt, 1444 (Pammel); 

 Ames, Iowa City (Hitchcock) ; Ames, 27 (Bessey) ; Lineville 

 (Shimek); Charles City (Pammel); Clermont (Walker). 



North America. In dry, open, woodland soil from New Jersey, 

 D. C. (Washington, Vasey), to Florida and Alabama; Washington 

 (Kittitas County, Sandberg), Missouri (Webster, Pammel). 



24. PANICUM UNCIPHYLLUM, 

 Panicum unciphyllum Trin. Gram. Pan. 242. 1826. Scribner and Mer- 

 rill. Rhodora 3: 121. 1901. Britton Man. 1040. 86. 



Panicum pubescens A. Gray, not Lam. Britton Man. 86. 



DESCRIPTION. 



An erect, or ascending, caespitose, 

 at length much branched, pubescent pe- 

 rennial, 1 to 2\ feet (3-8 dm.) high, 

 with lanceolate leaves, exserted, ovate 

 panicles and pubescent spikelets. Culms 

 pilose with weak hairs; nodes sparingly 

 bearded or smooth ; sheaths striate, 

 loose, usually shorter than the inter- 

 nodes, pilose with spreading or ascend- 

 ing hairs; ligule a long-ciliate fringe; 

 leaf-blades ascending, firm or even 

 rigid, acuminate, slightly narrowed at 

 the rounded or truncate base, densely 

 pubescent beneath with short spread- 

 ing hairs, smooth above or often 

 with scattered papillate hairs 2 to 5 

 inches (4-10 cm.) long, 2 to 6 

 lines (5-12 mm.) wide. Panicles i\ 

 to 5 inches (5-10 cm.) long, usually 

 purplish, the branches spreading, 

 generally few-flowered. Spikelets 

 elliptical, obtuse, (1.5 mm.) long;first 

 glume small, about one-fourth as long 

 as the spikelet; second and third 



an „ . • , „ , k glumes equal, pubescent with spread- 



FlG. 60. Panicum unciphyllum.— a. b, » _ M ' r 



Spikelets. (Charlotte M. King. ) ing hairs. 



