98 NORTH AMERICAN FLORA [VoLumE 17 
Extravaginal stolons present in addition to the intravaginal; stems usually much-branched. 
Spikelets with the back of the first scale glabrous, or with a few short hairs 
at the base. 1. E. tripsacoides. 
Spikelets with the first scale densely hairy on the back, 2. £, ciliaris. 
Extravaginal stolons wanting, only intravaginal ones present; spikelets densely 
hirsute, 3, E. barbiculmis. 
1. Elyonurus tripsacoides H. & B.; Willd. Sp. Pl. 4: 941. 1806. 
Rotiboellia ciliata Nutt. Gen. 1: 83. 1818. 
Andropogon tripsacoides H. & B.; Steud. Syn. Gram. 364. 1855. 
Andropogon Nuitallit Chapm. Fl. S. U. S. 580. 1860. 
Elionurus Nutlallianus Benth.; Vasey, Grasses U. S.171. 1883. 
Elionurus Nutlailii Vasey, Cat. Grasses U. S. 25. 1885. 
A tall perennial with both intravaginal and extravaginal innovations. Stems up to 1.5 
m. tall, glabrous, branching, the branches long and solitary; leaf-sheaths glabrous; blades 
up to 5 dm. long, prominently nerved, glabrous on the lower surface, the inner surface 
glabrous excepting at the hirsute base; racemes up to 1.5 dm. long, the internodes and 
pedicels ciliate on the margins with long hairs and hirsute on the back, the inner surface 
glabrous ; sessile spikelets 7-9 mm. long, lanceolate, acuminate, the first scale glabrous on 
the back or with a few hairs at the base, the margins wing-keeled and hispidulous above 
the middle with short hairs, the apex deeply 2-toothed, the teeth subulate; pedicellate 
spikelets 5-6 mm. long, glabrous or puberulent. 
TYPE LOCALITY: Caracas, Venezuela. 
DISTRIBUTION : Georgia and Florida to Texas, and south to northern South America. 
ILLUSTRATIONS: H.B.K. Nov. Gen. & Sp. 1: pl. 62; Bull. U. S. Dep. Agr. Agrost. 17: 7. 308 ; 
Beal, Grasses N. Am. 2: f. 23. 
2. Elyonurus ciliaris H.B.K. Nov. Gen. & Sp. 1: 193. 1816. 
Tripsacum ciliare Rasp. Ann. Sci. Nat. 5: 306. 1825. 
Elionurus tripsacoides ciliaris Hack. in DC. Monog. Phan. 6: 333. 1889. 
Elionurus tripsacoides sericeus Hack. in DC. Monog. Phan. 6: 334. 1889. 
A tall perennial with both intravaginal and extravaginal innovations. Stems up to 1 
m, tall, glabrous, branched, the branches long and solitary; leaf-sheaths, at least the lower 
ones, ciliate on the margins and usually papillose-hirsute; blades up to 2 dm. long, invo- 
lute, less than 1 mm. in diameter, prominently nerved, glabrous on the lower surface, or 
with a few long hairs at the base, densely hirsute on the upper surface; racemes 1 dm. 
long or less, the internodes and pedicels long-hairy on the margins and hirsute on the 
back, the inner face glabrous; sessile spikelets 7-9 mm. long, lanceolate, acuminate, the 
first scale hirsute on the back, the margins wing-keeled and hispidulous with short hairs, 
the apex deeply 2-toothed, the teeth subulate, the second scale shorter and thinner, pubes- 
cent; pedicellate spikelets about 5 mm. long, pubescent. 
TYPE LOCALITY: In woods along the Orinoco, near Esmeralda, at the foot of Mt. Duida, south- 
ern Venezuela. 
DISTRIBUTION: Mexico to Venezuela. 
ILLUSTRATION: H.B.K. Nov. Gen. & Sp. 1: pl. 63. 
3. Elyonurus barbiculmis Hack. in DC. Monog. 
Phan. 6: 339. 1889. 
A tufted perennial with intravaginal innovations, and simple or sparingly branched 
stems. Stems 46 dm. tall, pilose below the nodes with ascending hairs, otherwise glabrous ; 
leaf-sheaths usually long-ciliate on the margins, otherwise glabrous; blades complanate, 
erect, prominently 5-7-nerved, upto 2 dm. long, 1 mm. wide or less, ciliate on the margins 
with very long hairs, the upper surface densely hirsute; racemes 1 dm. long or less, the 
internodes and the pedicels ciliate on the margins with very long hairs, hirsute on the back, 
the inner face glabrous; sessile spikelets 6-9 mm. long, the first scale densely hirsute with 
erect hairs, ovate to ovate-lanceolate when spread out, at the apex very acute and slightly 
2-toothed to long-acuminate, with 2 long subulate teeth, the second scale thinner and shorter, 
hirsute; pedicellate spikelets 4-6 mm. long, hirsute. 
TYPE LOCALITY: Western Texas. 
DISTRIBUTION: Western Texas to Arizona, south to Durango. 
ILLUSTRATIONS: Bull. U. S. Dep. Agr. Agrost.7: 4.7, 20: f. 12; Bull. U.S. Dep. Agr. Bot. 
lal: pl. Ls. 
