HITCHCOCK AND CHASE NORTH AMEEICAN PANICUM. 243 



Vieginia: Region of Cape Henry, Chase 2349, 5428, Hitchcock 407, Kearney 1393, 



1454, 1776, 2114, Pollard & Maxon in 1900. 

 North Carolina: Wilmington, Chase 3161, 4601, Hitchcock 326, 336. 

 South Carolina: Isle of Palms, Chase 4544. 

 Georgia: Augusta, Kearney 209. 

 Florida: East Pass, Tracy 9141. 



^ 144. Panicum addisonii Nash. 



Panicum addisonii Nash, Bull. Torrey Club 25:83. 1898. "Collected by Mr. 

 E. P. Bicknell in sandy soil at Wildwood, N. J., May 30 and 31, 1897." The type 

 specimen, in Nash's herbarium, is the early branching form with culms 15 to 30 cm. 

 high, mature primary panicles, and spikelets 2 to 2.1 mm. long. 



Panicum oioenae Bicknell, Bull. Torrey Club 35:185. 1908. "Type collected 

 September 20, 1907, on the sandy commons west of the town [Nantucket], deposited 

 in herb. N. Y. Bot. Garden." The type specimen is the autumnal form, the primary 

 panicles destitute of spikelets, the secondary panicles among the crowded autumnal 

 leaves. The blades are nearly smooth except for scattered long hairs near the margin. 

 The vernal form collected by Bicknell at the type locality June 20, 1908, is' more 

 pubescent.' 



DESCRIPTION. 



Vernal form similar to that of P. commonsianum and often closely resembling that 

 species; culms more slender, rarely as much as 40 cm. high, appressed or ascending- 

 pilose at least below, puberulent above; sheaths sparsely ascending-pilose; blades 

 stiffly ascending, 4 to 7 cm. long, 3 to 6 mm. wide, involute-pointed, glabrous on the 

 upper surface, sometimes with a few long hairs near the margin, pubescent or glabrous 

 beneath; panicles long-exserted, 2 to 6 cm. long, two- thirds to three-fourths as wide, 

 the stiff branches ascending, the panicle thus ap- 

 pearing more densely flowered; spikelets 2 to 2.1 

 mm. long, 1.1 mm. wide, obovate, blunt, papillose- 

 pubescent, or the papillae obscure; first glume one- 

 third to half as long as the spikelet, usually pointed ; 

 second glume and sterile lemma barely equaling the 

 fruit at maturity; fruit 1.7 mm. long, 1 mm. wide, 

 elliptic, subobtuse. 



Autumnal form more or less spreading, rather ^ „^, „ j^- - t. 



, . ' ., Fig. 261.— p. addisomi. From 



freely branching from all the nodes, the branches ' type specimen. 



appressed or narrowly ascending, the later branch- 

 lets somewhat fascicled, the stiff blades not greatly reduced, overtopping the num- 

 erous reduced panicles. 



This species very closely approaches forms of P. commonsianum, the smaller, 

 broader spikelets with shorter first glume affording about the only constant difference, 

 though it is P. commonsianum rather ,than P. addisonii which varies much. The 

 type of P. oivenae and a specimen collected by Steele, Suitland, Maryland, in 1899, 

 both late autumnal forms, have fascicled primary branches from the lower nodes. 

 Usually only the secondary branchlets are fascicled. Two southern specimens. 

 Chase 4580 and Hitchcock 557, have laxer culms and more spreading branches. 



