No. 16. 
SPOROBOLUS ARGUTUS Kth. (Vilfa Arkansana Trin. Vilfa argua 
Nees.) 
Plant annual, smooth throughout except the scabrous margins of the leaves. 
Culm tufted, spreading, weak, branching below, smrooth, 6 to 12 inches tall. 
Leaves of radical shoots numerous, with mostly smooth, loose, scarious sheaths 
and flat blades 2 to 3 inches long; of culm 2 or 3, lower sheaths mostly shorter 
than internodes, close; blades like those of radical shoots, but upper ones much 
shorter; ligule a line of short tawny bristles. 
Inflorescence a rather narrow or sometimes spreading, erect panicle, 2 to 3 
inches long, often included at base; branches 3 to 5 at base, alternate above, divided 
and bearing many pedicellate spikelets on the outer two-thirds. 
Spikelets oblong-ovate, 1-flowered, ? line long; first glume oblong, obtusish, 
thin, hyaline, smooth, 1-nerved, } line long; floral glume lance-ovate cute, thin, 
1-nerved, $line long; palet broadly ovate, thin, obscurely 2-nerved, ne long. 
Grain elliptical, compressed, light-brown, with reddish scar, ut -ular, falling 
free. 
PLate XVI; a, empty glumes enlarged; 6, floral glume and palet inclosing 
grain. 
Texas to Arizona and Mexico. 
