glume absent; second glume and sterile lemma about equal, 5-nerved, the broad 

 intemerves infolded, densely villous; sterile lemma with a small palea and some- 

 times with a staminate flower; fertile lemma cartilaginous, brown, with narrow 

 pale hyaline margins, cymbiform, 3-nerved, subacute. 

 An American genus of 2 species. 



1. Blades erect or spreading, rather blunt or rounded at apex, linear, folded at 

 base; panicle usually purple 1. A. rufa. 



1. Blades ascending or spreading (on the average shorter and broader than in 

 A. rufa), tapering to apex, rounded at base; panicle usually pale.... 

 2. A. villosa. 



1. Anthaenantia rufa (Ell.) Schult. Fig. 139. 



Culms slender, 6-12 dm. tall; blades elongate, 3-5 mm. broad, often scabrous; 

 panicle 8-15 cm. long, usually purple; spikelets 3-4 mm. long. 



Infrequent in wet savannahs and sandy woodlands, e. and s.e. Tex., summer- 

 fall; Coastal States, N. C. to Tex. 



2. Anthaenantia vUIosa (Michx.) Beauv. Fig. 139. 



Differing from A. rufa in the broader, mostly shorter, spreading blades and in 

 the usually pale panicles. 



Rare in sandy woodlands and wet savannahs, in mud on edge of ponds, s.e. 

 and e. Tex., summer-fall; Coastal States, N.C. to Tex. 



48. Digitaria Fabr. Crabgrass 



A genus of several hundred species in warm regions, sometimes made to include 

 the related genera Trichachne and Leptoloma. The introduced annual crabgrasses, 

 D. sanguinalis, and the more abundant native D. adscendens and D. diversiflora 

 are persistent and pernicious weeds in the loamy soil of plowed fields, lawns and 

 flowerbeds. 



1. Digitaria sanguinalis (L.) Scop. Northern crabgrass. Fig. 140. 



Tufted and/ or usually stoloniferous annual freely rooting at the nodes; culms 

 15-90 cm. long, 1-3 mm. thick, usually long-decumbent, ascending only at the 

 ends; ligule a thin scale 1-2 mm. long; blades 2-7 cm. long, 3-10 mm. broad, 

 flat, usually crisped, sparsely or usually densely papillose-pilose; sheaths papillose- 

 pilose; panicle axis 1-15 (-30) mm. long; racemes 2 to 11, 4-12 cm. long, 1-2 

 mm. thick, often purplish, the wing of the rachis as broad as the central rib; spike- 

 let 2.3-3.2 mm. long; first glume present but minute; second glume 1-1.9 mm. 

 long, narrow, a third to three fifths (usually half) as long as the spikelet; sterile 

 lemma as long as the spikelet, usually with a sparse short antrorse-appressed silky 

 fringe on the margins and the 2 to 4 lateral nerves usually with minute inflexible 

 pointed cilia (as seen under a powerful lens); "fruit" (the lemmas and its 

 enclosures) often pale-plumbeous. 



Disturbed soil along roads, in fields and gardens, along irrigation ditches, 

 margin of ponds and spring branches and wet gravel bars, in Okla. (LeFlore, 

 Ottawa and Mayes cos.), frequent in the Tex. Plains country and infrequent to 

 Trans-Pecos, n.-cen. and e. Tex., s. as far as Travis and Gonzales cos., summer- 

 fall; s. Can., N. E., s. to Va., w. and s.w. to Wash., Calif, and Tex.; scattered in 

 U. S.; also Son., Chih. and Dgo.; introd. from n. Eur., now widespread in temp, 

 areas. 



49. Eriochloa H. B. K. Cupgrass 



Tufted annuals or perennials; inflorescence an elongate panicle of racemes 

 attached in 2 rows along 1 side of a more or less flattened axis (or on 2 sides 

 when the axis is vaguely broadly triangular in transection); racemes with more 



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