516 POACE^. 



a. Empty glumes spongy 2 



B. Spikelets 3-4 mm. long 3 



C. Spikelets 7-8 mm. long 4 



D. Spikelets 12-16 mm. long 5 



1. U. latifolia Michx. Fl. Bor. Am. 1:71 (1803). 



Culms rather stout, 60-120 cm. high. Leaves numerous, 

 sheatlis mostly shorter than the internodes; 

 ligule a fringe of very short hairs; blades lanceo- 

 late, about 11-ribbed, 10-18 cm. long, 1.5-2.5 cm. 

 wide. Panicle loose, noddiug, 18-30 cm. long. 

 Spikelets pedicellate, drooping, oblong, acute, 2-3 

 em. long, 10-1 5 -flowered, empty glumes subequal, 

 linear-lanceolate, 5-9 mm. long; floral glume 10- 

 13 mm. long, ovate-lanceolate, the keel winged 

 and ciliate; j^alea falcate, shorter than its glume. 

 Stamen 1. 



YiG.lOb.—Uniola Delaware, Canhy ; Illinois, Mead; Texas, 



let. (Scribuer!) Hall '793, Dnwwwtid ; New Mexico, Fendler 914. 



Eiver-banks, soutlieru Pennsylvania to Illinois, Florida, and 



New Mexico. 



2. U. paniculata L. Sp. PI. 71 (1753). Sea-oats. 



Culms stout, hard, 1-3 m. high. Ligule a fringe of hairs; 

 blades very long, rigid, soon involute or convolute. Panicle open, 

 <lrooping, 30-60 cm. long. Spikelets on short pedicels, whitish or 

 straw-colored, 2-2.4 cm. long, oblong, about 12-flowered; empty 

 glumes glabrous, 6-8 mm. long, spongy, 3-nerved ; floral glume 10- 

 12 mm. long, 7-nerved, keel not winged nor ciliate; palea scarcely 

 falcate, serrulate on the keels. Stamens 3. 



North Carolina, Hyams ; Floritla, Garber ; Texas, Wright. 



Sand-hills along the seacoast, Virginia to Florida, and Mexico 

 to Ecuador. 



3. U. laxa (L.) H. S. P. Prel. Cat. N. Y. 69 (1888). Holcus 

 laxus L. Sp. PI. 1048 (1753). U. gracilis Michx. Fl. Bor. Am. 

 1:71 (1803). 



Culms slender, GO-120 cm. high. Sheaths smooth or downy; 

 ligule a ciliate ring; l)lades 20-30 cm. long, 3-5 mm. wide, flat or 



