26 



CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



DESCRIPTION. 



Fig. 5.— P. ramisetum. 

 specimen. 



From type 



Plants pale green, tufted, from short horizontal rootstocks; culms erect or ascending, 

 25 to 60 cm. high, commonly branching at the base and lower nodes, scabrous at least 



below the nodes; sheaths nearly as long as the 

 internodes or the lower overlapping, not com- 

 pressed, sparingly papillose-pilose, especially 

 along the margins and at the summit; ligule 

 about 1 mm. long, with longer hairs at the sides; 

 blades rather firm, erect or ascending, 5 to 12 cm. 

 long, the lower shorter and more spreading, 2 to 

 4 mm. wide, tapering to an involute tip, not 

 narrowed at base, but about as broad as the 

 sheath, sparsely papillose-pilose on both sur- 

 faces, at least toward the base; sometimes 

 sparsely cilia te; panicles very slender, 5 to 20 

 cm. long, not conspicuously interrupted, their 

 branches erect, the ultimate branchlets of 1 to 4 subsessile spikelets, the setiform 

 prolongation of the axis usually not exceeding the short-pediceled spikelet; 

 spikelets 2.4 to 2.6 mm. long, 1.4 to 1.5 mm. wide, obovate, subacute, turgid, 

 plano-convex; first glume clasping, 

 about half the length of the spikelet, 

 subacute or acute, 5-nerved; second 

 glume and sterile lemma subequal, 

 scarcely covering the fruit at matu- 

 rity, strongly 7 to 9-nerved; fruit 2.2 

 to 2.3 mm. long, 1.4 mm. wide, ellip- 

 tic, acute. 



DISTRIBUTION. 



Sandy plains and prairies, southern 

 Texas and northern Mexico. 



Texas: Big Springs, Tracy 7958, 8229; Kingsville, Tracy 8879; Encinal, Griffiths 

 6380; Laredo, Nealley in 1891, Pringle 2377, Sauvignet in 1891; Eagle Pass, 

 Eavard 98; San Diego, Nealley 62, Smith in 1897; without locality, Buckley 

 in 1881, Nealley in 1887, 1888, 1889, and 1892. 

 Mexico: State of Coahuila, near Diaz, Pringle 8323. 



Fig. 6.— Distribution of P, ramisetum. 



5. Panicum reverchoni Vasey. 



Panicum reverchoni Vasey, U. S. Dept. Agr. Div. Bot. Bull. 8: 25. 1889. "Texas 

 (Reverchon)." The type, in the National Herbarium, was collected by J. Rever- 

 chon, near Dallas, Texas, and distributed in "Curtiss, North American Plants No. I," 

 as Setaria uniseta Fourn. 



DESCRIPTION. 



Plants tufted from short rootstocks, branching at the base; culms stiffly erect, 30 to 

 70 cm. high, simple or occasionally bearing one or two sterile branches, slender, sub- 

 compressed, glabrous or the lower internodes strigose, the nodes appressed-pubescent; 

 sheaths mostly longer than the internodes, ciliate on the margin toward the summit, 

 otherwise glabrous, often slightly scabrous, or the lowermost sometimes sparsely 

 strigose; ligule about 0.3 mm. long; blades erect, stiff, 5 to 20 cm. long, 2 to 3 mm. wide, 

 flat or involute toward the apex and base (the blades of the basal shoots commonly 

 involute-setaceous), scabrous on both surfaces, especially the upper, at the base nar- 

 rower than the sheath, the lower commonly disarticulating at this point; panicles 



