94 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
DISTRIBUTION, 
Arroyos and sandhills, western Texas, New Mexico, and northern Mexico. 
Texas: Guadalupe Mountains, //avard in 1881; without locality, Nealley in 1887. 
New Mexico: Las Vegas, Vasey in 1880; Roswell, Griffiths 5735. 
Mexico: Paso del Norte, Pringle 1124 (Hitchcock Herb.). 
46. Panicum amarum [fill. 
Panicum amarum Ell. Bot. 8. C. & Ga. 1: 121. 1816. ‘‘ Grows among the sand- 
hills on the seashore,’ presumably of South Carolina and Georgia. No specimen of 
this could be found in the Elliott Herbarium.¢ The description is as follows: ‘‘ Plant 
very glabrous; leaves thick, glaucous; panicle appressed; glumes acuminate. oot 
perennial? Stem 2-3 feet high, columnar, thick, nearly an half inch in diameter. 
Leaves nearly flat, almost coriaceous, the margins very entire; sheaths shorter than the 
joints, tinged with yellow; the throat contracted, purple; stipules villous. Panicle 
large, branches all appressed. Flowers very large. Peduneles, which in every other 
species are very scabrous, and generally hairy, are glabrous and nearly smooth. 
Calyx 2-flowered, hermaphrodite and male; valves glabrous and tinged with purple. 
Corolla, valve of the male floret as 
large as those of the hermaphrodite. 
* * * Grows among the sandhills 
on the seashore. Leaves excess- 
ively bitter.’”’ The greater part of 
this description will be seen to apply 
equally well to the cespitose species 
to which the name P. amarum has 
been applied and to P. amaroides 
Scribn. & Merr. Scribner and Mer- 
rill> accepted the cespitose form as 
the true P. amarum, but the fact 
that ?. amaroides and not the cespi- 
tose species grows on the coast of 
North and South Carolina, and espe- 
cially that it is abundant on the Isle 
of Palms in Charleston Harbor, Elli- 
ott’s own locality, casts doubt on the 
correctness of this identification of 
Elliott’s species. In the description 
quoted above “Panicle appressed” 
seems to indicate P. amaroides, as 
does the query after ‘root peren- 
nial.’’ There could be no doubt 
about the cespitose species (unless one had only a specimen without the base), 
while in P. amaroides the horizontal rootstock is deep in the sand and the solitary 
culms are readily detached from it. ‘‘Stem 2-3 feet high” applies much better to 
P. amaroides, since the allied species is rarely as low as 3 feet. ‘Leaves excessively 
bitter” is true of P. amaroides while those of the cespitose species are but slightly or 
not at all bitter. On the whole the evidence is so strongly in favor of P. amaroides as 
Fia.85.—P.amarum. From type specimen of ?. amarum 
minus Vasey. 
a Scribner and Merrill (U. 8. Dept. Agr. Div. Agrost. Cire. 29: 5. 1901) state that 
“The specimen in the Herbarium of Elliott under this name is a robust form of 
Panicum virgatum Linn,’’ This name, however, was added later, since it is initialed 
“H.W. RR.’ [Ravenel.] The original label bears an unpublished name, 
5U,8. Dept. Agr. Div. Agrost. Circ, 29; 5. 1901, 
