528 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
Duranoo: Durango, Palmer 175 in 1896, Hitchcock 7618. Torreén, Hitchcock 7563. 
Coanutta: Saltillo, Palmer 394 and 504 in 1898, Hitchcock 5582. La Ventura, 
Nelson 3908. Jaral, Schumann 1714. 
Nuevo Lr6é6n: Monterrey, Hitchcock 5533. 
ZACATECAS: Concepcién del Oro, Palmer 
266in 1904. Zacatecas, Hitchcock 7525. 
AGUASCALIENTES: Aguascalientes, Rose & 
Hay 6231, Hitchcock 7456. 
San Luts Potosi: San Luis Potos{, Palmer 
590 in 1898, Parry & Palmer 960 in 
1878, Schaffner 148, Hitchcock 5657. 
Guanasuato: Obregén, Hitchcock 5801, 
Irapuato, Hitchcock 7407. 
QueERETARO: San Juan del Rfo, Rose, 
Fra. 140.—Distribution of P. obtusum, Painter & Rose 9552, 9594. Querétaro, 
Hitchcock 5813, 5863. 
Hrpaueo: Tula, Rose, Painter & Rose 8356. Ixmiquilpan, Rose, Painter & Rose 
9057. 
Puesuia: Tehuacan, Hitchcock 6060. 
RepuBiic or Mexico: Without locality, Hartweg 244. 
112. Panicum stagnatile sp. nov. 
DESCRIPTION. 
Plants perennial, gregarious; culms erect from an ascending or decumbent base 
rooting at the nodes, somewhat lush, 1 to 2 meters high, about 5 mm. thick, glabrous, 
simple or occasionally with sterile branches; nodes glabrous or the lower retrorsely 
appressed-pubescent; sheaths usually about as long as the internodes or the upper 
overlapping, ciliate on the margin, otherwise glabrous or pubescent on the sides at 
the junction with the blade; ligule membranaceous, less than 1 mm. long; blades 
flat, 20 to 35 cm. long, 1.5 to 3 cm. wide, slightly narrowed to the rounded base, taper- 
ing from below the middle to an acuminate apex, sparingly pilose above the ligule, 
otherwise glabrous, the margins scabrous; panicle 20 to 40 cm. long, about half as 
wide, fusiform in outline, the main axis and rachises strongly 
angled, scabrous, usually sparsely pilose in the lower axils, the 
numerous slender, compound branches rather stiffly ascending 
or spreading, solitary or irregularly fascicled, bearing from near 
the base and usually along the lower side rather stiffly spreading 
slender secondary branchlets, the lower 1 to 2 cm. long; spike- 
lets loosely clustered, short-pediceled, glabrous, 1.8 mm. long, 
about 0.6 mm. wide, acute; first glume about one-third as long 
as the spikelet, acute, scabrous on the keeled midnerve, the 
second glume two-thirds as long as the spikelet, somewhat boat- 
shaped, scabrous on the keel, the sterile lemma slightly exceeding the fruit, boat- 
shaped and scabrous on the midnerve at the apex; fruit 1.6 mm. long, 0.4 mm. wide, 
lanceolate, scabrous at the acute apex, the lemma and palea subindurate, the margins 
of the lemma inrolled only at the base. 
Type in the U. 8. National Herbarium, no. 693328, collected in water of swamp, 
Frijoles, Canal Zone, Panama, October 12, 1911, by A. 8. Hitchcock (no. 8388). 
This species is allied to P. rivulare Trin. but differs in the broader blades, less densely 
flowered panicle branches, and smaller spikelets. The numerous small spikelets and 
slender branchlets give the panicle a lacelike appearance. The type locality is now 
covered by the water of Gatun Lake. 
Fig. 141.—P. stagnatile. 
From type specimen. 
