66 



CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



Mexico: Near International Boundary, Mearns 2294, Merton 1705; northern 

 Sonora, Griffiths 6758, 6799, 6892; Nogales, Hitchcock 3631; Llano, Hitch- 

 cock 3526; Hermosillo, Hitchcock 3541, 3573, 3604; Guaymas, Hitchcock 3547 , 

 3553, Palmer 208 and 346 in 1887; Alamos, Palmer 695 and 750 in 1890; 

 Purisima, Lower California, Brandegee 8 in 1889, 42 in 1899; State of Chihua- 

 hua, Nelson 6297, 6355, Palmer 1 b in 1885 in part; Topolobampo, Palmer 249 

 and 251 in 1897; Culiacan, Palmer 1544, 1545, and 1554 in part in 1891. 



Galapagos Islands: Agassiz in 1891. 



26. Panicum pampinosum sp. nov. 



DESCRIPTION. 



Plants freely branching from the base; culms ascending from a decumbent base, 



branching at the lower and middle nodes, compressed, glabrous, or sparsely pilose 



below the panicle, the nodes pubescent; sheaths 

 loose, papillose-hispid, ciliate; ligules of very 

 stiff hairs 2 to 3 mm. long; blades 5 to 12 cm. 

 long, 5 to 10 mm. wide, flat, scarcely narrowed 

 at the rounded or subcordate base, sparsely 

 pilose above, sparsely hispid beneath, the 

 margin pilose and more or less undulate; pan- 



¥iil\ HWJ iff II il II 111! If i ll'il ide 9 long-exserted, 6 to 15 cm. long, half to 



two-thirds as wide, the branches solitary, the 

 lower as much as 5 to 8 cm. long, often bear- 

 ing a branchlet at base, stiffly ascending, 

 bearing several, mostly short, appressed 

 branchlets with rather crowded, sbort-pedi- 

 celed spikelets; spikelets about 4 mm. long, 

 1.4 mm. wide, very turgid, pointed; first glume 

 more than three-fourths the length of the 



spikelet, pointed; second glume and sterile lemma subequal, exceeding the fruit 



and pointed beyond it, the sterile palea short; fruit 2.2 mm. long, 1.3 mm. wide, oval, 



an indistinct scar at the base. 



Type U. S. National Herbarium 



no. 592754, collected August 25, 1903, 



on range reserve, altitude 2,600 feet, 



Wilmot, Arizona, by Prof. J. J.Thornber 



(no. 193). 



DISTRIBUTION. 



On mesas, New Mexico and Arizona. 



New Mexico: Organ Mountains, 

 Wooton 2014; Grant County, 

 Rusby 444; without locality, 

 Wright 2084. 



Arizona: -Tucson Mountains, Griffiths 6939 J; Wilmot, Thomber 193 and Septem- 

 ber 3, 1903 (the latter in Univ. Ariz. Herb.). 



26 A. Panicum decolorans H. B. K.o 



Fig. 48. 



-P. pampinosum. 

 specimen. 



From type 



Fig. 49. — Distribution of P. pampinosum. 



a While this revision was in press this species was collected by A. S. Hitchcock at 

 its type locality, Queretaro, Mexico. It has therefore been removed from the list of 

 doubtful species. The description and illustration will be found on page 328. 



