66 



GRASSES OF IOWA. 



description'. 



Sprouting Crab Grass. 

 A smooth, usually much 

 branched annual, with 

 stems 2 to 4 or 6 feet, 

 rather coarse, spreading or 

 ascending (rarely erect) 

 (5-10 or 14 dm.) long, 

 flat leaves and diffuse ter- 

 minal and lateral panicles. 

 Sheaths smooth, lax, some- 

 what flattened ; ligule dil- 

 ate; leaf-blade 6 to 12 

 or 24 inches (12-24 or 

 48 cm.) long, 2 to 10 lines 

 (4-20 mm.) wide, acute, 

 scabrous on the margins 

 and sometimes also on the 

 prominent nerves, rarely 

 pilose on the upper surface; 

 panicles pyramidal, 4 or 5 

 to 12 or 15 inches (8 or 

 10-24 or 30 cm.) long, the 

 primary and secondary 

 branches spreading, scab- 

 Vlr , ,„ D ,- c r. ,, , ,. ■, rous. Spikelets rather 



Fig. 46. Panic um proliferum.—a,, b, c, spikelets ;d, ^ 



e, flowering glume. (Div. of Agros. LJ. S. Dent, of crowded upon short, ap- 

 Agrl. ) 



pressed and scabrous pedi- 

 cels, lanceolate ovate, acute, 1 to 1 1 lines (2-3 mm.) long, smooth, green 

 or purplish ; lowest glume embracing the base of the spikelet, usually 

 obtuse and nerveless, rarely one to three-nerved, one-fourth to one- 

 third as long as the nearly acute five to seven-nerved second and third 



