74 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
long, about 1 mm. wide; first glume about two-thirds the length of the spikelet, 
acuminate, 3 to 5-nerved, second glume and sterile lemma 5 to 7-nerved; fruit 1.5 
to 1.7 mm. long, about 0.8 mm. wide, elliptic. 
This species has been confused with both P. diffusum and P. hallii, to both of which 
it is closely related. From the first 1t is distinguished by the taller, erect or nearly 
erect culms, and wider blades glabrous 
and glaucous on the upper surface. 
The typical form has a much more 
loosely-flowered panicle than has P. 
diffusum, but most of the specimens 
are less well marked. From P. hallii it 
is distinguished by the looser panicles 
of usually longer pediceled, smaller 
spikelets, by the usually taller culms 
and longer blades, often equaling or 
exceeding the panicle. 
The following specimens have spike- Fig. 61.—Distribution of P. filipes. 
lets 2.8 to 3 mm. long and appear to be 
intermediate between P. filipes and P. hallii, Texas: Abilene, Bentley in 1899; 
Daffan, Bodin 310; Dallas, Bush 1156; Spofford, Griffiths 6323; Olmito, Tracy 8908; 
Corpus Christi, /Teller 1490. Mexico: Guerrero, Lagunillas, Langlassé 263. 
A specimen from ‘‘Overflow land along Colorado River,’’? southern California, 
Schellenger 3, is doubtfully referred here. It appears to be an annual but is probably 
P. filipes fruiting the first year from seed. 
DISTRIBUTION. 
Low open ground or among chaparral, southern Texas. 
Texas: Arlington, Reverchon 3526; Terrell, Warburton in 1904; Burnet, Plank 38; 
Llano, Plank 2; Kingsville, Piper in 1906; Houston, Nealley in 1886; Hemp- 
stead, Thurow in 1906; Kerrville, [eller 1883 in part; Seguin, Plank 97; Abi- 
lene, Bentley in 1899; Del Rio, Plank 85; San Diego, Nealley in 1894; Encinal, 
Griffiths 6387; Corpus Christi, Nealley 28 in 1891, in 1893 and 1894; Santa 
Maria, Nealley in 1889; Brownsville, /litehcock 220, without locality, Buckley 
in 1881 and 1883, Drummond 286, 384, 394, Nealley in 1888, 
35. Panicum hallii Vasey. 
Panicum hallit Vasey, Bull. Torrey Club 11: 64. 1884. ‘‘This is number 816 of 
E. Hall’s Texas collection, distributed as P. giganteum, Scheele.’’ The type, in the 
National Herbarium, was collected on ‘‘Dry hills, 
Austin, Eastern Texas, May 18, 1872, by Elihu 
Nall.” Two species were distributed by Hall un- 
der 816, the other being P. filipes. 
DESCRIPTION. 
Plants rather glaucous green, in small tufts, erect, 
15 to 60 cm. high; culms simple or sparingly branch- 
ing from the lower nodes, glabrous except the ap- 
pressed-pubescent nodes; leaves commonly more or 
less crowded toward the base, the blades becoming 
curled or twisted, the lower sheaths overlapping on 
theshort internodes; sheathssparsely papillose-hispid 
to glabrous; ligules about 1.5 mm. long; blades erect 
or nearly so, 4 to 15 cm. long, 2 to 6 mm. wide, flat, usually sparsely papillose-ciliate 
toward the base, otherwise glabrous or with a few long, delicate hairs on the upper 
Fic. 62.—P. hallii. From type 
specimen. 
