Chase — Notes on Genera of Panice&. IV. 155 



Trinius, Nees, and Steudel, of the earlier authors, include Echinochloa, 

 usually as a section, in Panicum. 



Kunth (II. B. K. Nov. Gen. & Sp. 1 : L06. 1816; Rev. Gram. 1 : 4:;. 

 L829; Enum. 11. 1 : 138. L833) and Desvaux (Opusc. si. L831) include it 

 under OpHsmenus. 



Roemer & Schultes (Syst. Veg. 2 : 47(>. 1817), Schultes (Mant. 2 : 266. 

 1824), and Link (Hort. Berol. 2 : 208. 1833) give Echinochloa generic 

 rank, hut the latter adds (op. cit. 209) " < ienera Echinochloa et Panicum 

 artincialia sunt, nee natura distincta." 



Of the later authors Bentham (Fl. Hongkong 411. 1861; Fl. Austr. 7 : 

 47s. 1878; Benth. & Hook. Gen. PI. 3 : 1102. 1883), Grisebach (Fl. Brit. 

 \V. End. 545. 1804), Doell (Mart. Fl. Bras. 2 2 : 139. 1877) and Hackel 

 (Engler & Prantl, Pflanzenf. 2 2 : 35. 1887) include Echinochloa in Pani- 

 cum. Fournier (Mex. PL 2 : 39. 1886) includes E. crusgalli and its 

 close allies in OpHsmenus, but OpHsmenus holciformis H. B. K., a long- 

 awned species allied to E. spectabilis (Nees) Link, he places in Berch- 

 toldia (misspelled " Berchtholdia" ). In his key to Paniceae (op. cit. 

 3) Fournier distinguishes Berchtoldia from OpHsmenus by the "remote 

 inferior glume." (Both genera are included under " Spiculis involucra- 

 tis; involucro constante e spiculis abortivis," as opposed to "e chaeto- 

 cladis" including Setaria, Pennisetum, etc. What Fournier could have 

 mistaken for an involucre of abortive spikelets is not evident.) 



Nash (Britton, Man. 78. 1901; Small, FL Southeast. U. S. 84. 1903) 

 and Hitchcock (Gray, Man. ed. 7. 117. 1908) recognize Echinochloa as a 

 valid genus. 



Description. — Inflorescence paniculate, the usually compact, densely 

 dowered panicle composed of one-sided simple racemes or of subsiinple 

 branches; spikelets plano-convex, often spiny-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, the lemma 

 long-awned, in some species conspicuously so, enclosing a membranace- 

 ous palea and sometimes a staminate flower; fruit plano-convex, the 

 lemma and palea smooth and shining, acuminate-pointed, the lemma 

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

 Coarse, often succulent annuals, with compressed sheaths and linear, flat 

 blades; species of the temperate and tropical regions, two species cosmo- 

 politan. 



In this genus the awn of the sterile lemma is exceedingly variable in 

 length, sometimes even in the same plant. Echinochloa is distinguished 

 from Panicum constantly by the plano-convex, pointed fruit, the lemma 

 margins flat above, the apex of the palea free, and usually by the awned 

 sterile lemma. 



A Mexican species described under OpHsmenus belongs to this genus: 



Echinochloa holciformis (H. B. K. ). 



OpHsmenus holciformis H. B. K. Nov. Gen. & Sp. 1 : 107. 1816. "Crescit 

 in humidis montanis prope Cinapecuaro, alt. 970 hexap. (Regno Mexi- 



