MANUAL OF THE GRASSES OF THE UNITED STATES 



693 



upper approximate; spikelets crowded, about 3 mm long, excluding 

 the awns; internerves hispidulous ; nerves strongly tuberculate- 

 hispid; awn variable, mostly 5 to 10 mm long on at least some of the 

 spikelets, sometimes as much as 3 cm. o Moist open places, 

 ditches, cultivated fields, and 

 waste ground, New Brunswick to 

 Washington, south to Florida 

 and California, mostly at low 

 and medium altitudes; Eastern 

 Hemisphere. Echinochloa muri- 

 cata (Michx.) Fernald is differ- 

 entiated by Fernald from E. 

 crusgalli by the stiff hairs arising 

 from papillae on the spikelets, 

 true E. crusgalli as he under- 

 stands it having hairs that lack 

 the papillose base. The author 

 has been unable to separate E. 

 muricata, the European speci- 

 mens having on the average as 



FiGUEE 1556. Echinochloa crusgalli var. frumewtacea, 

 X 1. (Piper, Tex.) 



strongly tuberculate spikelets 

 as Michaux's specimen. The 

 three following varieties inter- 

 grade and can be only arbitra- 

 rily distinguished. 



ECHINOCHLOA CKUSGALLI 

 var. MITIS (Pursh) Peterm. 

 (Fig. 1554.) Spikelets awnless 

 or nearly so, the awns less than 

 3 mm long, o Moist places 

 over about the same area as the 

 species and nearly as common. 

 ECHINOCHLOA CRUSGALLI var. 

 ZELAYENSIS (H.B.K.) Hitchc. 

 (Fig. 1555.) Differs from E. 

 crusgalli var. mitis in having 

 less succulent culms, mostly 

 simple, more or less appressed 

 racemes, the spikelets less 

 strongly hispid but papillose, usually green. Small plants resem- 

 ble E. colonum, but differ in the more distinctly pointed spikelets, 

 more spreading racemes, and erect more robust culms, o Moist, 

 often alkaline places, Oklahoma to Oregon, south to Texas and Cali- 



FIGUEE 1557. Echinochloa crus-pavonis, X 1. (Sintenis 

 1889, P.R.) 



