54. Echinochloa Beau v. Water Grass 



Annual or rarely perennial; culms rarely erect, often rooting at the nodes; 

 leaves membranous, flat; ligule absent in most species; inflorescence an elongate 

 terminal panicle of numerous ascending spikelike branchlets that are secundly 

 flowered on the abaxial side; spikelets paired in the upper nodes of the spikelike 

 branchlets and in several-flowered secondary panicles in the lower part, not at 

 all compressed, 2-flowered (the lower floret usually completely reduced, rarely 

 staminiferous), turgidly plano-convex; first glume about half as long as the 

 spikelet, acute; second glume and sterile lemma membranous, equal, about as 

 long as the spikelet, usually stiffly hispidulous along the several nerves, acute; 

 glume usually coarsely mucronate or awned (if awned, the awn of the second 

 glume much longer than that of the first); sterile lemma enclosing a thin palea 

 and rarely 3 stamens and often awned; fertile lemma broadly elliptical, cartilagin- 

 ous-indurate, acuminate, the lateral margins revolute, clasping the lateral margins 

 of the similarly textured palea but not its acute free tip. 



A genus of perhaps 25 species of warm regions. They are excluded from 

 Panicum on the bases of the form of the inflorescence, the usually very coarsely 

 pubescent spikelets and the coarsely mucronate or awned glumes. Probably they 

 represent merely a part of the very diverse genus Panicum, and should be placed 

 therein. These plants are commonly found in muddy places and provide good 

 forage locally. 



The seeds of these species provide imjwrtant food for ducks and many other 

 kinds of birdlife. 



1. Ligule a row of stiff yellowish hairs; body of sterile lemma 4-5 mm. long.... 

 5. E. polystachya. 



1. Ligule obsolete or absent; body of sterile lemma 2.5-4 mm. long (2) 



2(1). "Spikes" of inflorescence 3-20 (-40) mm. long, ascending, often diverging 

 from the axis at angles of 20°^5°, only shortly if at all overlap- 

 ping; blades 3-6 mm. broad 1. E. colonum. 



2. "Spikes" of inflorescence 10-100 mm. long, ascending or slightly diverging, 



often overlapping a considerable portion of their lengths; blades 

 mostly broader than 5 mm. (3) 



3(2). Inflorescence thick, if slender then erect; sterile lemmas unawned or with 

 awns to 10 mm. long 2. E. crusgalli. 



3. Inflorescence slender, nodding, dense; sterile lemmas with awns ,4—43 mm. 



long (4) 



4(3). Sheaths usually papillose-pilose or papillose-hispid; spinulose cilia of the 

 nerves of the second glume and sterile lemma conspicuously papil- 

 lose 4. E. Walteri. 



4. Sheaths glabrous; spinulose cilia of the nerves of the second glume and sterile 



lemma not conspicuously papillose 3. E. cruspavonis. 



1. Echinochloa colonum (L.) Link. Jungie-rice. Fig. 166. 



Diffuse annual; culms erect or procumbent and rooting at the nodes. 1-2 (-3) 

 mm. thick basally; ligule obsolete; "spikes" 3-20 (-40) mm. long, ascending, 

 appressed or often diverging from the axis at angles of 20°— 45°, remote on the 

 axis, only shortly if at all overlapping; second glume and sterile lemma simply 

 strongly acuminate, not awned, hispid along the nerves (use lens), about 3 mm. 

 long. Panicum colonum L. 



In water of freshwater canals, ditches and pools, in marshes, Okla. (McCurtain, 

 Johnston and Cherokee cos.), nearly throughout Tex. (infrequent in Plains 

 Country) in moist loamy often disturbed soil, N. M. (Lea and San Juan cos.) and 

 Ariz. (Yavapai, Graham, Pinal, Maricopa, Cochise, Santa Cruz, Pima and 



326 



