140 NORTH AMERICAN FLORA [VoLuME 17 
scale membranous, hyaline, subtending a hyaline palet and a perfect flower. Stamens 3. 
Styles short, distinct. Stigmas moderately long, plumose. 
Type species, Cenchrus racemosus L. 
Spikelets 2-3 mm. long, the spines not exceeding 0.5 mm. in length, the very stout 
swollen opaque base usually longer than the translucent apex. 1. MN, aliena, 
Spikelets 4-4.5 mm. long, the longer spines often 1mm. long, the opaque some- 
what swollen base usually shorter than the translucent apex. 2. N. racemosa. 
1. Nazia aliena (Spreng.) Scribn. Bull. U. S. Dep. Agr. 
Agrost. 17: 28. 1899. 
Lappago racemosa H.B.K. Nov. Gen. & Sp. 1: 119. 1815. Not ZL. racemosa Willd. 1798. 
Lappago aliena Spreng. Neue Entdeck. 3:15. 1822. 
Tragus alienus Schultes; R. & S. Syst. Veg. Mant.2: 205. 1824. 
Tragus Berteronianus Schultes, in R. & S. Syst. Veg. Mant. 2: 205. 1824, 
Tragus occidentalis Nees, Agrost. Bras. 286. 1829. 
Nazta occidentalis Scribn. Zoe 4: 386. 1894. 
Nazia racemosa aliena Scribn. & Sm. Bull. U. S. Dep. Agr. Agrost. 4:12. 1897, 
Stems tufted, up to 3 dm. tall, often rooting at the lower nodes and there sending up 
tufts of erect branches; leaf-sheaths smooth and glabrous; blades up to 8 cm. long, usually 
shorter, 2-4 mm. wide, flat, or involute on the ciliate margins, otherwise glabrous; inflores- 
cence up to 1 dm. long, usually 6 cm. or less, often included at the base; spikelets numerous, 
2-3 mm. long, the second scale with the spines 0.5 mm. long or less, the stout swollen opaque 
base longer than the translucent more slender apex. 
TYPE LOCALITY: Brazil. 
DISTRIBUTION : Southern and western Texas to Arizona and northern Mexico, and throughout 
tropical America ; occasional as a waif or adventive in the eastern United States. 
ILLUSTRATIONS: Bull. U.S. Dep. Agr. Agrost. 17: f. 324; 20: f. 16 ; Bull. U. S. Dep. Agr. Bot. 
121; pl. 14 ee vacemosus) ; Britt. & Brown, Ill. Fl. A 226 (as WV. racemosa) ; Beal, Grasses 
N. Am. 2: 
2. Nazia racemosa (I,.) Kuntze, Rev. Gen. 780. 1891. 
Cenchrus racemosus 1,. Sp. Pl. 1049, 1753. 
Phalaris muricata Forsk, Fl. Aegypt.-Arab. 202. 1775. 
Tragus racemosus All. Fl. Ped. 2: 241, 1785. 
Tragus muricaius Moench, Meth. 53. 1794. 
Lappago racemosa Willd. Sp. Pl. 1: 484, 1798. 
Stems up to 4 dm. tall, often rooting at the lower nodes and there sending up tufts of 
erect branches; leaf-sheaths smooth and glabrous; blades up to 6 cm. long, usually less than 
4 cm., 2-4 mm. wide, flat, ciliate on the margins, otherwise glabrous; inflorescence 2-8 cm. 
long, often included at the base; spikelets 4-4.5 mm. long, the spines with the somewhat 
swollen opaque base shorter than the translucent apex, the longer ones often 1 mm. in length. 
TYPE LOCALITY: Southern Europe. 
DISTRIBUTION : Occasionally introduced about cities or as a ballast waif; native of the warm 
temperate and tropical regions of the Old World. 
ILLUSTRATIONS: Host, Gram. Austr. 1: pl. 36; Sibth. Fl. Graeca pl. 101; Nees, Gen. FI. 
Germ. 7Jragus. 
35. LEPTOTHRIUM Kunth, Rév. Gram. 156. 1829. 
Glabrous tufted grasses, with rigid branching stems, short rigid leaf-blades, and shortly 
pedicellate spikelets borne alternately in a slender inflorescence. Spikelets 1-flowered, on 
angled pedicels which are articulated with the rachis, of 3 scales and a palet; empty basal scales 
2, coriaceous, subulate, the first a little the shorter, somewhat keeled, ciliate on the margins, 
the second convolute, enclosing the flowering scale; flowering scale hyaline, 1-nerved, ovate, 
somewhat keeled, enclosing a palet of similar texture about one third its length and a perfect 
flower; lodicules 2, broadly cuneate, very thinly membranous, hyaline, about one half the 
length of the ovary, truncate or sinuately lobed at the apex. Stamens 3. Ovary glabrous, 
with 2 short terminal styles. Stigmas penicilliform, with the hairs somewhat branched. 
Type species, Leptothrium rigidum Kunth. 
1. Leptothrium rigidum Kunth, Rév. Gram. 156. 1829, 
Stems 2-4 dm. tall; leaf-sheaths longer than their involute blades, which are 1.5-3 cm 
long; inflorescence 4-8 cm. long; spikelets 5-6 mm. long, on stout pedicels 1-2 mm. long. 
