94 



CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



DISTRIBUTION. 



Arroyos and sandhills, western Texas, New Mexico, and northern Mexico. 

 Texas: Guadalupe Mountains, Havard 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 Ell. 



Panicum amarum Ell. Bot. S. 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. a The description is as follows: "Plant 

 very glabrous; leaves thick, glaucous; panicle appressed; glumes acuminate. Root 

 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. Peduncles, 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 b accepted the cespitose form as 

 the true P. amarum, but the fact 

 that P. 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 



a Scribner and Merrill (U. S. Dept. Agr. Div. Agrost. Circ. 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. R." [Ravenel.] The original label bears an unpublished name. 



&U. S. Dept. Agr. Div. Agrost. Circ. 29: 5. 1901, 



Fig. 85.— P. amarum. 



From type specimen of P. amarum 

 minus Vasey. 



