u 



CONTRIBUTIONS FKOM THE NATIONAL HERBAKIUM. 



Fig. 61.— Distribution of P. filipes. 



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 it 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- 

 lets 2.8 to 3 mm. long and appear to be 

 intermediate between P. Jllipes and P. hallii. Texas: Abilene, Bentley in 1899; 

 Daffan, Bodih 310; Dallas, Bush 1156; Spofford, Griffiths 6323; Olmito, Tracy 8908; 

 Corpus Christi, Heller 1490. Mexico: Guerrero, Lagunillas, Langlasse 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, Heller 1883 in part; Segum, Plank 97; Abi- 

 lene, Penney 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, Hitchcock 220, without locality, Buckley 

 in 1881 and 1883, Drummond 286, 384, 394, Nealley in 1888. 



35. Panicum hallii Vasey. 



Panicum hallii 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 

 Hall." 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 

 the short internodes ; sheaths sparsely 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 



FlG. 62 P. hallii. From type 



specimen. 



