HITCHCOCK AND CHASE—NORTH AMERICAN PANICUM. 249 
and base, the long hairs sometimes mixed with appressed pubescence beneath; panicles 
1.5 to 4 cm. long, about as wide; spikelets 1.3 to 1.4 mm. long, rounded obovate, very 
turgid, pubescent; second glume shorter than the fruit at maturity; fruit 1.1 mm. long, 
0.8 mm. wide, obtuse. 
Autumnal form widely spreading, the branches appearing earlier than in the species, 
shorter and usually more crowded and somewhat aggregated toward the summit. 
A few specimens intermediate between the species and subspecies occur, as Kearney 
10, District of Columbia, which has the habit and pubescence of the subspecies but 
spikelets 1.5 mm. long; Chase 3559, Atsion, New Jersey, and Commons 58, Rehoboth, 
Delaware, which have the stouter culms and crisped pubescence of the species but 
spikelets 1.4 mm. long. Short speci- 
mens with much crowded branches 
resemble P. oricola, from which they 
may be distinguished by the smaller 
spikelets and less dense pubescence. 
DISTRIBUTION. 
Dry sands, Massachusetts to Virginia. 
Massacuusetts: Nantucket, Bick- 
nell in 1899 and 1904. 
New Jersey: Mantoloking, Lyon 
in 1902; Atsion, Chase 3534, Fic. 270.—Distribution of P. columbianum thinium. 
3560, Saunders & Clute 2;'TToms 
River, Chase 3577; Forked River, Chase 3588; Tuckerton, Chase 3605. 
Mary.anp: Hyattsville, Chase 3806. 
Virania: Lynn Haven, Hitchcock 406. 
148. Panicum oricola Hitchc. & Chase. 
Panicum oricola Hitche. & Chase, Rhodora 8: 208. 1906. ‘‘Type Hitchcock 47 in 
National Herbarium. Prostrate clumps on bare sand on low mounds between marsh 
and sand dune. Lewes, Del., June 18, 1905, collected by A. 8. Hitchcock.”’ This 
specimen is the early autumnal form. 
DESCRIPTION. 
Vernal form grayish, often purplish; culms densely tufted, 10 to 30 em. high, 
spreading, densely appressed or ascending pilose, the hairs on the nodes spreading; 
sheaths usually more than half the length of the internodes, appressed-pilose; ligules 
1 to 1.5 mm. long; blades firm, erect or ascending, 2 
to5ecm. long, 2 to4 mm. wide, broadest near the base, 
acuminate, the upper surface pilose with hairs 3 to 5 
mm. long, the lower surface appressed-pubescent with 
longer hairs intermixed; panicles short-exserted, or 
rarely long-exserted early in the season, 1.8 to 3 cm. 
long, rarely longer, about two-thirds as wide, rather 
densely flowered, the axis appressed-pubescent, the 
flexuous branches ascending or spreading; spikelets 
1.5 mm. long, 1 mm. wide, broadly obovate, turgid, obtuse, pubescent with short 
spreading hairs; first glume one-third to half the length of the spikelet, abruptly 
pointed; second glume and sterile lemma barely equaling the fruit at maturity; fruit 
1.3 mm, long, 0.9 mm. wide, broadly elliptic, very turgid. 
Fia. 271.—P. oricola. From type 
specimen. 
