MANUAL OF THE GRASSES OF THE UNITED STATES 711 



141. ECHINCCHLOA Beauv. 



Spikelets planoconvex, often stiffly hispid, subsessile, solitary or in irregular 

 clusters on one side of the panicle branches; first glume about half the length 

 of the spikelet, pointed; second glume and sterile lemma equal, pointed, 

 mucronate, or the glume short-awned and the lemma long-awned, sometimes 

 conspicuously so, enclosing a membranaceous palea and sometimes a staminate 

 flower; fertile lemma planoconvex, smooth and shining, acuminate-pointed, 

 the margins inrolled below, flat above, the apex of the palea not enclosed. 

 Coarse, often succulent, annuals or perennials, with compressed sheaths, linear 

 flat blades, and rather compact panicles composed of short, densely flowered 

 racemes along a main axis. Type species, Echinochloa crusgalli. Name from 

 Greek echinos, hedgehog, and chloa, grass, alluding to the echinate spikelets. 



All the species are grazed by stock but usually grow in sparse stands or in 

 situations where they cannot well be utilized. E. crusgalli is occasionally cut 

 for hay. Echinochloa crusgalli var. frumentacea, Japanese millet, has been 

 advertised by seedsmen in this country as billion-dollar grass and recommended 

 for forage. It has some forage value, but requires considerable moisture to 

 produce abundantly, and is rather too succulent for hay. This and forms of 

 E. colonum are cultivated in tropical Asia and tropical Africa for the seeds 

 which are used for food. 



Ligule a dense line of stiff yellowish hairs; plants perennial 1. E. polystachya. 



Ligule wanting; plants annual. 



Racemes simple, rather distant, 1 to 2 cm. long; spikelets crowded in about 4 rows, the 

 awn of the sterile lemma reduced to a short point; blades 3 to 6 mm. wide. 



2. E. COLONUM. 

 Racemes more or less branched, usually more than 2 cm. long; spikelets irregularly 

 crowded and fascicled, usually not arranged in rows, the awn of the sterile lemma 

 variable; blades usually more than 5 mm. wide. 



Sterile floret staminate 5. E. paludigena. 



Sterile floret neuter. 



Sheaths smooth; awns variable, but the panicle not a dense mass of long-awned 

 spikelets. 

 Panicles erect and rather stiff (heavy panicles somewhat nodding) ; spikelets con- 

 spicuously hispid 3. E. crusgalli. 



Panicles soft and nodding; spikelets inconspicuously hispid. 



4. E. CRUS-PAVONIS. 



Sheaths, at least the lower, hispid or scabrous (glabrous in forma laevigata) ; panicle 

 dense, the spikelets long-awned 6. E. walteri. 



1. Echinochloa polystachya (H. B. 



K.) Hitchc. (Fig. 1084.) Aquatic or 15 mm. long. % — Swamps and 



subaquatic; culms coarse, 1 to 2 m. ditches near the coast, Louisiana and 



tall, from a long creeping base, gla- Brownsville, Tex.; West Indies to 



brous; nodes glabrous or obscurely Argentina. 



pubescent; sheaths glabrous or very 2. Echinochloa colonum (L.) Link, 



sparsely papillose; ligule a dense line Jungle-rice. (Fig. 1085.) Culms 



of stiff yellow hairs as much as 4 prostrate to erect, 20 to 40 cm. long; 



mm. long; blades 30 to 40 cm. long, blades rather lax, 3 to 6 mm. wide, 



1.5 to 2.5 cm. wide, scabrous on the occasionally transversely zoned with 



margin; panicles mostly 15 to 25 cm. purple; panicle 5 to 15 cm. long; 



long, dense, the short thick branches racemes several, 1 to 2 cm. long, 



ascending; pedicels with stiff hairs 3 appressed or ascending, single or 



to 5 mm. long; spikelets about 5 mm. occasionally two approximate, the 



long, the nerves papillose-hispid, the lower usually distant as much as 1 



sterile floret staminate; awns 2 to cm.; spikelets about 3 mm. long, 



