1921] Wiegand, — Eehinochloa in North America 51 



g. Leaves entirely green 1. E. colonum. 



g. Leaves cross-banded with purple forma zonalis. 



/. Panicle broader, often ovoid, open or dense; 

 branches longer (2-6, rarely -9 cm. long), 

 usually compound and usually more densely 

 flowered; spikelets larger, 2.5-4 mm. long, 

 ovoid or oval, obtuse to strongly acute or 

 awned, echinate or unarmed; leaf-blades 5- 

 30 mm. broad. 

 g. Coriaceous lemma subacute; spinules min- 

 ute and almost uniform in size or want- 

 ing; lower palet often wanting; anthers 

 0.7-1 mm. long; nodal and branch-setae 

 of the panicle much reduced or wanting 

 (spinules scarcely swollen at base). 

 h. Spikelets 3.3-4 mm. long, 1.7-2 mm. 

 broad, awnless, soft-tipped; coriaceous 



lemma 2.7-3 mm. long 2. E. zdayensis. 



h. Spikelets 2.5-3 mm. long, 1.1-1.5 mm. 

 broad, sometimes awned; coriaceous 

 lemma 1.9-2.5 mm. long. 



i. Spikelets awnless, soft-tipped var. macera. 



i. Spikelets or some of them short- 



awned var. sabaristata. 



g. Coriaceous lemma in most spikelets ob- 

 tuse; spinules if present more strongly 

 developed on the sides of the spikelet 

 or on the lower lemma; lower palet pres- 

 ent; anthers 0.6-0.85 mm. long; nodal 

 and branch-setae usually well developed; 

 (spikelets 2.8-3.7 mm. long, 1.5-2.3 mm. 

 broad). 

 h. Spikelets with very short inconspicuous — 

 mostly slender-based spinules, or these 

 nearly wanting, subglabrous, broad 

 and turgid, mostly obtuse and soft- 

 tipped, awnless; lower palet almost al- 

 ways purple; panicle dense, chocolate- 

 purple, the branches often incurved at 

 apex; leaves in well-developed speci- 

 mens 15-25 mm. broad 3. E. frumentacea. 



h. Spikelets with numerous spinules of me- 

 dium length, the lateral usually with 

 swollen bases, less turgid, strongly 

 apiculate, firmer-tipped; lower palet 

 whitish; panicle usually rather open, 

 with straight spreading branches, green 

 or purple; leaves 15 mm. broad or less. 

 i. Awns none, or a few spikelets with 



short awns 4. E. crusgalli. 



i. Awns prominent, longer, many or all 



of the spikelets awn-bearing forma longiseta. 



e. Coriaceous lemma subacuminate, the tip firmer; 

 spikelets from moderately to very strongly 

 echinate, often appearing very hispid even to 

 the unaided eye; (branch- and nodal setae 

 usually poorly developed). 

 /. Spikelets large, 3.3 4.5 mm. long, 1.8-2.2 

 mm. broad; anthers 0.7-0.8(-0.9) mm. long. 



