156 NORTH AMERICAN FLORA [VOLUME 17 
pedicel below the scales, 1- or 2-flowered, in pairs, in two rows along one side of the flat rachis, 
placed face to face, the primary with a short pedicel and containing a perfect flower, the second- 
ary nearly sessile, usually abortive, rarely developed or wanting. Fertile spikelets laterally 
compressed. Scales 4; first and second scales firm and broad, acuminate, one or both of them 
echinate at maturity, the first straight, equaling the spikelet, the second shorter; third scale 
acuminate, broad, enclosing a palet of nearly equal length and often also a staminate flower; 
fourth or fruiting scale with a minute basal wing or thickening, indurated, plano-convex, 
elliptic, with the margins flat, or inrolled only at the summit. Stamens 3. Styles distinct. 
Stigmas plumose. 
Type species, Echinolaena hirta Desv. 
1. Echinolaena polystachya H.B.K. Nov. Gen. & Sp. 1: 119. 1815. 
Panicum uncinatum Raddi, Agrost. Bras. 41. 1823. 
Panicum heteranthum Link, Hort. Berol.1: 212. 1827, 
Panicum glandulosum Nees, Agrost. Bras. 128. 1829. 
Echinolaena Trinii Zoll. & Mor.; Moritzi, Syst. Verz. Zoll. 102. 1846. 
Stems up to 8 dm. long, prostrate and branching at the base and rooting at the lower 
nodes; leaf-sheaths hispid; blades up to 8 cm. long, 1.5 em. wide, flat, ovate-lanceolate to 
elliptic, acuminate, hispid; inflorescence up to 1 dm. long, of several rather distant erect or 
ascending racemes 1-3 cm. long; spikelets 3.5-4 mm. long. 
pe LOCALITY: On the banks of the Magdalena River, between Tenerife and Zambrano, 
Colombia. 
DISTRIBUTION: Southern Mexico to Brazil. 
ILLUSTRATIONS: Trin. Ic. pl. 216; H.B.K. Nov. Gen. & Sp. £1. 679, 
48. MESOSETUM Steud. Syn. Gram. 118. 1854. 
Slender perennial grasses, with narrow leaf-blades, and a single terminal spike-like raceme. 
Spikelets articulated to the pedicel below the scales, 1- or 2-flowered, singly disposed in two rows 
on one side of a 3-angled flexuous rachis which is rarely winged, the back of the fruiting scale 
turned away from the rachis, the side toward the rachis swollen and fitting into its cavities, 
the other side flat. Scales 4; first and second 3—5-nerved, the lateral nerves sometimes uniting 
with the midnerve above, often with stiff hairs on the margin; third scale similar to the outer 
ones in texture and pubescence, often appearing 2-keeled on account of the weak midnerve 
and the thin hyaline middle internerve, sometimes enclosing a palet and also a staminate 
flower; fourth or fruiting scale swollen on the face, its back flat, pointed, somewhat indurated, 
its margins not hyaline. Stamens 3. Styles distinct. Stigmas plumose. 
Type species, Mesosetum cayennense Steud. 
Spikelets copiously hairy; first scale asymmetric, longer than the second. 1. M. lolitforme. 
Spikelets glabrous or merely hispid; first scale symmetric, shorter than the 
second. 2. M. Wrightii. 
1. Mesosetum loliiforme (Hochst.) Chase, Bot. Gaz. 51: 302. 1911. 
Panicum lolitforme Hochst.; Steud. Syn. Gram. 56. 1854. 
A stoloniferous perennial. Stems tufted, up to 7 dm. tall, erect, pubescent at the nodes; 
leaf-sheaths papillose-hispid with spreading hairs; blades up to 8 cm. long, 3~6 mm. wide, flat, 
or involute on the margins, papillose-hispid on both surfaces, hispid-ciliate on the cartilaginous 
margins; raceme up to 1.5 dm. long, slender, long-exserted; spikelets 3-3.5 mm. long, the 
outer 3 scales copiously hairy, 3-nerved, the first scale oblong, asymmetric, rounded at the apex, 
longer than the lanceolate acute second, the third scale broadly elliptic, acute, the fruiting 
scale broadly lanceolate, acute. 
TYPE LOCALITY: Surinam. 
DISTRIBUTION : Cuba; also in Surinam. 
2. Mesosetum Wrightii Hitchc. Contr. U. S. Nat. 
Herb. 12: 211. 1909. 
Stems 2-4 dm. tall, slender, glabrous, geniculate or creeping at the base; leaf-sheaths 
ciliate on the margin, hispid at the summit, or the lower ones hispid throughout; blades 3-6 
