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 1b in 1885 in part; Topolobampo, Palmer 249 
and 251 in 1897; Culiacdan, 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 
specimen. 
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- 
icles long-exserted, 6 to 15 cm. long, half to 
two-thirds as wide, the branches solitary, the 
lower as much as 5 to 8 em. 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, 
1.4mm. 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 2.2mm. long, 1.3 mm. wide, oval, 
an indistinct scar at the base. 
Type U. 8. National Herbarium 
no. 592754, collected August 25, 1903, 
on range reserve, altitude 2,660 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. 
Fie, 49.— Distribution of P. pampinosum. 
Arizona: Tucson Mountains, Griffiths 69394; Wilmot, Thornber 193 and Septem- 
ber 3, 1903 (the latter in Univ. Ariz. Herb.). 
26A. Panicum decolorans H. 3. K.¢ 
aWhile this revision was in press this species was collected by A. 8. Hitchcock at 
its type locality, Querétaro, Mexico. 
It has therefore been removed from the list of 
doubtful species. The description and illustration will be found on page 328. 
