138 POACEAE 



1. Polyodon Texanus (S. Wats.) Xash. Stems tufted, wiry, erect, slender, 1-4 dm. 

 tall : leaf-blades 2 dm. lono; or less, 1-2 mm. wide, often involute : panicle 3-6 cm. long, 

 of 5-8 short spreading spikes which arc 9-12 mm. long : spikelets 2-4 in each spike. 

 \_Bouleloua Tezcina S. Wats.] 



In dry soil, the Indian Territory and Texas. Spring and summer. 



87. ELEUSINE Gaertn. 

 Annual, or perennial and creeping, grasses, with flat leaf-blades, and an inflorescence 

 composed of normally several spikes arranged digitately or approximately with sometimes 

 an additional single spike below. Spikelets numerous, much crowded, imbricated, sessile, 

 alternate in 2 rows, several-flowered, the flowers perfect, or the upper ones staminate. 

 Scales several, obtuse or acute, flattened, keeled, thin, the 2 lower empty, a little shorter 

 than the others, the remaining scales usually more obtuse, each of the lower ones enclosing 

 a scarcely shorter compressed 2-keeled palet and a flower, the terminal scales empty. Sta- 

 mens 3. Styles distinct. Stigmas plumose. 



1. Eleusine Indica (L. ) Gaertn. Stems 1.5-6 dm. tall, erect, or decumbent at the 



base : leaf-sheaths loose, overlapping, often short and crowded at the base of the stem ; 



blades 7-30 cm. long, 2-6 mm. wide : spikes 2-10, whorled, or approximate at the summit 



of the stem, or sometimes with 1 or 2 distant ones, 2-8 cm. long : spikelets 3-4 mm. long, 



3-6-flowered. 



In waste places, fields and dooryards nearly throughout North America. Naturalized from the 

 Old World. Summer and fall. Wire'Grass. Yard Grass. Crab Grass. Dog Gra.ss. Crow-foot. 



88. DACTYLOCTENIUM Willd. 



Annual grasses, with flat leaf-blades and an inflorescence consisting of orie-sided spikes 

 terminally arranged in pairs or digitate. Spikelets numerous, crowded, imbricated, ses- 

 sile, alternate in 2 rows, several -flowered, the flowers perfect or the upper ones staminate. 

 Scales several, acute and mucronate-pointed, or the second awned, thin, flattened, keeled, 

 the 2 lower empty, the remaining scales broader, each of the lower ones enclosing a 

 scarcely shorter compressed 2-keeled palet and a flower, the upper scales empty. Stamens 

 3. Styles distinct. Stigmas plumose. 



1. Dactyloctenium Aegyptium (L. ) Willd. Stems 1.5-6 dm. tall, usually decum- 

 bent and extensively creeping at tlie base : leaf-sheaths loose, overlapping, often crowded ; 

 blades 1.5 dm. long or less, 2-6 mm. wide, ciliate toward the base : spikes in pairs, or 3-5 

 and digitate, 1-5 cm. long : spikelets 3-5-flowered. l^Eleusine Aeyi/ptia Pers. ] 



In cultivated ground and waste places, southern New York, Pennsylvania and Virginia to Illinois, 

 California and Florida. Also widely distributed in tropical America. Naturalized from Asia or Africa. 

 Summer and fall. Egyptian Grass". 



89. LEPTOCHLOA Beauv. 

 Often tall grasses, with flat or convolute leaf-blades, and an inflorescence consisting of 

 very many long slender spikes arranged in a panicle, rarely approximate at the summit of 

 the stem. Spikelets small, close, or rarely scattered, 2-several-flowered, rarely 1 -flowered, 

 flattened, sessile, alternate in 2 rows. Scales 3-several, keeled, obtuse, acute, or shortly 

 awned, the 2 lower empty, a little unequal, usually shorter than the spikelet, or in the 

 1-flowered spikelets exceeding the third scale, the remaining scales more obtuse or some- 

 times bearing a slender awn, each of the lower enclosing a prominently 2-keeled palet and 

 a flower, the upper empty. Stamens 3. Styles distinct. Stigmas plumose. 



Spikes very slender, 1 mm. broad or less : empty scales generally about the same 

 length, the first from nearly equalling to exceeding the first howering scale. 

 Flowering scales l.Ti mm. long, the pubescence on the nerves long and copious. 1. L. mucronata. 

 Flowering scales less than 1 mm. long, the puVjescence on the nerves short and 



scant. 2. L. uttcnuata. 



Spikes stouter, 2 nnii. wide or more : empty scales usually very uneciual, the first 

 much shorter than the first fiowering scale. 

 Inflorescence generally loose and open, the branches elongated and more or less 

 spreading, usually in whorls or sometimes opposite or alternate. 

 Upper surface of the leaf-blades glabrous : scales of the spikelet usually 7-8, 

 the flowering ones awnless, or sometimes the first and rarely the second 

 short-awned. " 3. L. vircmla. 



Upper surface of the leaf-blades hirsute toward the base : scales of the spike- 

 let usually .5-6, the flowering ones all awned, the awn of the first more 

 than ^4 as long as the body. 4. /.. Domingcnms. 



Inflorescence long and narrow, the branches commonly short, erect or nearly 

 so, crowded and disposed in dense alternate fascicles. 



