Part 2, 1912] POACEAE 143 
2. Arundinella peruviana (J. Presl) Steud. Syn. Gram. 115. 1854. 
Thysanachne peruviana J. Presl, in Presi, Rel. Haenk,1: 253. 1830. 
Arundinella Deppeana Nees, Bonplandia 3: 84. 1855. 
Arundinelia cubensis Griseb. Mem. Am. Acad. II. 8: 533. 1862. 
Arundinella phragmitoides Griseb. Cat. Pl. Cub. 234. 1866. 
Arundinella robusta Fourn. Mex. Pl. Gram. 54. 1881. 
Arundinella latifolia Fourn. Mex. Pl. Gram, 54. 1881. 
Arundinella auletica Rupr.; (Galeotti, Bull. Acad. Brux. 9?: 242; hyponym. 1842) Fourn. Mex. 
Pl. Gram. 54. 1881. 
Arundinella scoparia Fourn, Mex. Pl. Gram. 55, in part. 1881. 
Stems up to 2-3 m. tall; leaf-sheaths hirsjtte or hispid toward the summit; blades up to 
5 dm. long and 2.5 cm. wide, glabrous, or hirsute or hispid on one or both surfaces; panicle 
up to 4 dm. long, dense and stout or loose and open, its branches usually long, erect or as- 
cending; spikelets, exclusive of the awn, 4-5.5 mm. long, the first scale 3-nerved, acute, one 
half to two thirds as long as the second, the second scale 5-nerved, long-acuminate, somewhat 
recurved above the middle, the apex obtuse, the third scale 5-7-nerved, from a little shorter 
to somewhat longer than the first scale, the fourth scale about 1.5 mm. long, the awn 8-10 mm. 
long, the column much longer than the scale, usually more than twice as long, commonly 
straight, sometimes twisted, rarely loosely spiral, shorter than the subula. 
TYPE LOCALITY: Huanuco mountains, Peru. 
DISTRIBUTION: Southern Mexico to Panama; Cuba; also in South America. 
ILLUSTRATION: Beal, Grasses N. Am. 2: f. 20, B, bd. 
39. TRISCENIA Griseb. Mem. Am. Acad. IIT. 8: 534. 1862. 
Tufted perennial grasses, with slender stems, triangular keeled leaf-blades, and a slender 
panicle. Spikelets singly arranged, articulated to the pedicels below the empty scales, 1- 
flowered. Scales 4, awnless, the three outer ones membranous, the fourth thinner, hyaline; 
first scale less than one half as long as the spikelet; second scale longer than the remaining 
scales; third scale a little shorter than the second scale; fourth scale about one half as long as 
the third. Stamens 3. Stigmas protruding above the middle of the spikelet. Caryopsis 
free, oblong; embryo minute. 
Type species, Triscenia ovina Griseb. 
1. Triscenia ovina Griseb. Mem. Am. Acad. II. 8: 534. 1862. 
Stems 1.5-3 dm. tall, about twice as long as the leaves of the innovations; leaf-sheaths 
broad, strongly striate, long-ciliate on the margins, otherwise glabrous; blades compressed- 
triangular in cross-section, slender, less than 0.5 mm. wide, up to 12 cm. long, glabrous, or 
sparingly hairy near the base; panicle slender, up to 1 dm. long, the branches slender and 
appressed; spikelets 3~3.5 mm. long, acuminate, the first scale 1-3-nerved, acute, the second 
scale 5-nerved, the third scale 3-nerved, or sometimes with a faint additional pair, the fourth 
scale faintly 3-nerved. 
TYPE LOCALITY: Cuba. 
DISTRIBUTION : Known only from the type locality. 
40. ARTHROPOGON Nees, Agrost. Bras. 319. 1829. 
Rather rigid grasses, with the leaves mainly toward the base of the stem, and a terminal 
spreading panicle, the spikelets with a ring of long hairs at the base. Spikelets articulated 
below the empty scales, solitary along the continuous branches of the panicle, the terminal 
flower perfect, sometimes with an additional lower staminate one. Seales 4; first and second 
empty, the former narrowed into an awn, the second longer, broader, and more rigid, obtuse 
or somewhat 2-toothed at the apex, the midnerve running out into an awn; third scale similar 
to the second but awnless, and often bearing a palet or staminate flower, or both; fourth scale 
shorter, awnless, thin and hyaline. Stamens 3. Styles distinct. Stigmas plumose. Cary- 
opsis free, but loosely enclosed in the rigid scales. 
Type species, Arthropogon villosus Nees. 
