GENERA OF GRASSES OF THE UNITED STATES. 
215 
second glume and sterile lemma about as long as the fruit, 3 to 
5 nerved, copiously silky ; fertile lemma cartilaginous, lanceolate, 
acuminate, usually brown, the flat white hyaline margins broad. 
Perennial grasses, the slender racemes erect or nearly so, aggregate 
along the upper part of the main axis, forming a white or brownish 
woolly panicle. Species about 12, in the warmer parts of America 
and in Australia ; 3 species in the southern United States. 
Type species: Andropogon insularis L. 
Valota Adans., Fam. PI. 2: 495. 1763. The citation given by Adanson is to 
" Sloan, t. 14. f. 2." which is also given by Linnaeus under his Andropogon in- 
sularis? which fixes this species as the type. 
Trichachne Nees, Agrost. Bras. 85. 1829. Nees describes five species, the first 
of which, T. insularis, based on Andropogon insularis, is taken as the type. 
Valota is closely allied to Syntherisma, differing chiefly in the 
acuminate fruit and the silky spikelets. 
Valota insularis (L.) Chase (Panicum lanatum Rottb., P. leuco- 
fhaeum H. B. K.) (fig. 129), common in the American Tropics, with 
brown or tawny inflorescence, is found in southern Florida. Valota 
hitehcockii Chase, with short blades and short-pubescent spikelets is 
a rare species from Texas and Mexico. Valota sacchamta (Buckl.) 
Chase (Panicum lachnanthum Torr.), with copiously long, silky 
white spikelets, is common in the Southwestern States on rocky soil. 
The first-mentioned species is not relished by cattle and in the West 
Indies is called sour-grass. The third species is a constituent of the 
ranges of the Southwest, but furnishes only fair forage. 
110. Synthekisma Walt., the crab-grasses. 
{Digitaria Hall., not Heist.) 
Spikelets solitary or in twos or threes, subsessile or short-pedi- 
celed, alternate in two rows on one side of a three-angled winged or 
wingless rachis; spikelets lanceolate or elliptic, plano-convex; first 
glume minute. or wanting; second glume equaling the sterile lemma 
or shorter ; fertile lemma cartilaginous, the hyaline margins pale. 
Annual or sometimes perennial, erect or prostrate grasses, the slen- 
der racemes digitate or somewhat scattered, but aggregate along the 
upper part of the culms. Species about 60, in the warmer parts of the 
world; 12 species in the United States, mostly in the southeastern 
part. 
Type species : Syntherisma praecox Walt. 
Digitaria Hall., Stirp. Helv. 2: 244, 1768, not Adans., 1763, nor Heist, 1759. 
Haller describes two species. No specific names are used, but the first species is 
associable by citation with Panicum sanguinale L. {Syntherisma sanguinalis) 
and the second with Panicum dactylon L. {Capriola dactylon). The first is 
chosen as the type. 
Syntherisma Walt., Fl. Carol. 76. 1788. Walter describes three species, S. 
praecox, S. serotina, and £. villosa. The first of these is selected as the type. 
This is the same as S. sanguinalis. 
1 Syst. Nat., ed. 10, 2: 1304. 1759. 
