MANUAL OF THE GRASSES OF THE UNITED STATES 



501 



less than 50 cm. long, but sometimes 

 as much as 1 m. ; blades flat or folded, 

 3 to 8 mm. wide; spikes mostly 2 to 

 6, rarely more, or but 1 in depauper- 

 ate plants, flat, 4 to 15 cm. long. O 

 — Waste places, fields, and open 

 ground, Massachusetts to South Da- 

 kota and Kansas, south to Florida 

 and Texas; occasional in Oregon, 

 Utah, Arizona, and California; intro- 

 duced ; a common weed in the warmer 

 regions of both hemispheres. 



Eleusine tristachya (Lam.) Lam. 

 Spikes 1 to 3, rarely more, 1 to 2.5 

 cm. long, 8 to 10 mm. thick; resem- 

 bling E. indica, but the spikes short 

 and thick. O — On ballast, Cam- 

 den, N. J. and Mobile, Ala. ; Portland, 

 Oreg. and elsewhere; tropical Africa; 

 introduced in tropical South America. 



Eleusine coracana (L.) Gaertn. 

 African millet. More robust than 

 E. indica; spikes thicker, heavier, 

 sometimes incurved at the tip, brown- 

 ish at maturity. A cultivated form of 

 E. indica', the seed used for food 

 among primitive peoples in Africa and 

 southern Asia. O — Occasionally 

 grown at experiment stations. Called 

 also ragi, coracan millet, and finger 

 millet. 



101. DACTYLOCTfiNIUM Willd. 



Spikelets 3- to 5-flowered, com- 

 pressed, sessile and closely imbricate, 

 in two rows along one side of the 

 rather narrow flat rachis, the end pro- 

 jecting in a point beyond the spike- 

 lets; rachilla disarticulating above the 

 first glume and between the florets; 

 glumes somewhat unequal, broad, 1- 

 nerved, the first persistent upon the 

 rachis, the second mucronate or short- 

 awned below the tip, deciduous; lem- 

 mas firm, broad, keeled, acuminate or 

 short-awned, 3-nerved, the lateral 

 nerves indistinct, the upper floret re- 

 duced; palea about as long as the 

 lemma; seed subglobose, ridged or 

 wrinkled, enclosed in a thin, early- 

 disappearing pericarp. Annuals or 

 perennials with flat blades and 2 to 

 several short thick spikes, digitate 

 and widely spreading at the summit 



of the culms. Type species, Dactyloc- 

 tenium aegyptium. Name from Greek 

 daktulos, finger, and ktenion, a little 

 comb, alluding to the pectinate ar- 

 rangement of the spikelets. 



1. Dactyloctenium aegyptium (L.) 

 Beauv. (Fig. 735.) Culms com- 

 pressed, spreading with ascending 

 ends, rooting at the nodes, branching, 

 commonly forming radiate mats, usu- 

 ally 20 to 40 cm. long, sometimes as 

 much as 1 m.; blades flat, ciliate; 

 spikes 1 to 5 cm. long. O — Open 

 ground, waste places, and fields, 

 Coastal Plain, North Carolina to 

 Florida and Texas; also occasional at 

 more northern points (Maine to New 

 Jersey; Illinois); Colorado, Arizona, 

 and California; tropical America; in- 

 troduced from Old World Tropics. 



102. MICROCHLOA R. Br. 



Spikelets 1-flowered, awnless, ses- 

 sile in 2 rows along one side of a nar- 

 row flattened rachis, the rachilla dis- 

 articulating above the glumes ; glumes 

 subequal, longer than the floret, 

 acute, 1-nerved; floret with a soft, 

 pointed callus ; lemma thin, 3-nerved, 

 flabellate; palea narrow, a little 

 shorter than the lemma. Slender per- 

 ennials with simple culms and slender 

 solitary falcate spikes. Type species, 

 Microchloa setacea R. Br. Name from 

 the Greek micros, small, and chloe, 

 grass. 



1. Microchloa kunthii Desv. (Fig. 

 736.) Perennial; culms very slender, 

 erect in small dense tufts, 10 to 30 

 cm. tall; sheaths, except the lower- 

 most, much shorter than the inter- 

 nodes, scaberulous; ligule ciliate, 1 to 

 1.5 mm. long; blades firm, flat or usu- 

 ally folded, with thick white scabrous 

 margins, those of the culm 1 to 2.5 

 cm. long, those of the innovations to 

 6 cm. long, 1 to 1.5 mm. wide; spike 

 6 to 15 cm. long, falcate, the rachis 

 ciliate; spikelets 2.5 to 3.5 mm. long; 

 lemma 2 to 2.5 mm. long, pilose on 

 the midnerve, the margins densely 

 ciliate with hairs about 1 mm. long. 

 % — Granitic outcrop on rocky slope, 

 Carr Canyon, Huachuca Mountains, 



