528 



CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



DuRANGO: Diirango, Palmer 175 in 1896, Hitchcock 7618. Torreon, Hitchcock 7563. 

 Coahuila: Saltillo, Palmer 394 and 504 in 1898, Hitchcock 5582. La Ventura, 



Nelson 3908., Jaral, Schumann 1714. 

 NuEVO Le6n: Monterrey, Hitchcock 5533. 



Zacatecas: Concepcion del Oro, Palmer 

 266 in 1904. Zacatecas, Hitchcock 7525. 

 Aguascalientes: Aguascali antes. Rose & 



Hay 6231, Hitchcock 7456. 

 San Luis Potosi: San Luis Potosi, Palm^ 

 590 in 1898, Parry & Palmer 960 in 

 1878, Schaffner 148, Hitchcock 5657. 

 Guanajuato: Obregon, Hitchcock 5801. 



Irapuato, Hitchcock 7407. 

 QuERETARo: San Juan del Rio, Rose, 

 Painter & Rose 9552, 9594. Queretaro, 

 Hitchcock 5813, 5863. 

 Hidalgo: Tula, Rose, Painter & Rose 8356. Ixmiquilpan, Rose, Painter & Rose 



9057. 

 Puebla: Tehuacdn, Hitchcock QQQO . 

 Republic of Mexico: Without locality, Hartweg 244. 



113. Paniciun stagnatile sp. nov. 



description. 



Fig. 140. — Distribution of P. obtusum. 



Plants perennial, gregarious; cubns 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 intemodes 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 aa 

 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 fi'om 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 inroUed only at the base. 



Type in the U. S. National Herbarium, no. 693328, collected in water of swamp, 

 Frijoles, Canal Zone, Panama, October 12, 1911, by A. S. 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. 



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