A 



^ 



^"^^ Nash : The diciiotomous Pamcums 



Panicum pernervosum 



I 



A glabrous perennial. Culms 3-5 dm. tall, finally branching ■ 

 leaves 3 or 4 ; sheaths ciliate on the exterior margin, the lower 

 longer, the upper shorter than the intcrnoctes ; ligule a dense ring 

 of hairs about 0.5 mm. long ; blades erect or ascending, narrowed 

 toward the base, serrulate and very rough on the margins, the 

 intermediate and upper blades 5-10 cm. long, 5-9 mm. wide 

 cihatc toward the base with a few long hairs, the lower ones usu- 

 ally pubescent on the lower surface, shorter and broader, ciliate for 

 two thirds their length : panicle considerably exscrted,' 7-12 cm. 

 long, its branches ascending, the larger ones 4-6 cm. long : spike- 

 lets 3 mm. long and 1.8 mm. wide, broadly oval, turgid, rounded 

 at the apex, the scales glabrous, the first scale broader than long 

 l-nerved, about one third as long as the spikelet, the second and 

 third scales coarsely 9-nerved, the second a little shorter than the 

 thu-d, the fourth scale yellowisli white, 2.5 mm. long and about 

 1.6 mm. broad, obtusely and rather obscurely apiculate. 



Type collected by Elihu Hail in woods, at Houston, Texas, 

 April 16, 1872, no. 830. Mr. G. C. Nealley also secured it in 

 the same state in 1886. 



Panicum psammophilum 



A tufted perennial. Culms 2-4 dm. tali, appressed-hirsute 

 below, puberulent above, finally much branched : leaves on the 

 mam culm about 4, occasionally 3 or 5 ; sheaths shorter than the 

 mternodes, apprcssed-pubcsccnt, the basal ones with long hairs, 

 the upper and those on the branches with very short hairs ; ligule 

 a dense ring of hairs about i mm. long ; blades erect or nearly so, 

 thick, firm, serrulate on the margins, puberulent beneath, the 

 ovate-lanceolate basal ones, and occasionally also those oii the 

 culm, with a few very long scattered erect hairs on the upper sur- 

 face, the primary blades lanceolate, 2-5 cm. long, 2-5 mm. wide 

 those on the branches 2^3 cm. long, 2-3 mm. wide ; primary 

 panicle broadly ovate, usually 2-3 cm. long, rarely larger, its axis 

 and usually ascending branches puberulent : spikclets broadly ob- 

 ovate, 1. 3-1. 5 mm. long, rarely a little larger, and 0.8-1 mm. 

 Wide, obtuse, the outer 3 scales densely pubescent with spreading 

 hairs, the first scale usually about one third as long as the spikelet, 

 sometimes a little larger, i -nerved, orbicular or broadly ovate,' 

 acute or obtuse, the second and third scales 9-ncrved, the sec- 

 ond usually a little shorter than the third, the fourth scale yel- 



lowish, 1. 2- 1. 5 mm. long, oval. 



scy. Specimens examined : 



Massachusetts to New J 



