532 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
wide, ovoid in outline, the main axis pilose, the numerous delicate but rather stiff 
brahches ascending at a uniform angle (in herbarium specimens the branches con- 
spicuously parallel), the numerous but not crowded 
spikelets recurved at right angles on capillary pedi- 
cels; spikelets 1.2 mm. long, about 0.7 mm. wide, 
strongly plano-convex, turgid; first glume nearly as 
long as the spikelet, 3-nerved, narrow, covering the 
middle internerves of the sterile lemma, thin in tex- 
ture and so closely appressed as to be usually invisi- 
ble, sparsely hispid; second glume inflated, gibbous, 
pointed, 5-nerved, papillose-hispid, at maturity sub- 
indurate, the hairs stiffening and as much as 1 mm. 
long; sterile lemma equaling the second glume and 
inclosing a 2-keeled palea, 5-nerved, glabrous, the two 
middle internerves thin; fruit 1 mm. long, 0.6 mm. 
wide, very turgidly plano-convex, at first white, at 
maturity brown, sparsely sprinkled with minute glob- 
ular hairs. 
The spikelets of this unique species at maturity look like tiny burs or, as Lamarck 
says, like the ‘‘seeds of Daucus.’’ The bristly second glume sometimes falls, leaving 
the turgid fruit, together with the first glume and sterile lemma, attached to the 
pedicel. 
Fig. 148 —P. hirtum. From type 
specimen. 
DISTRIBUTION. 
Damp shady places, Trinidad to 
Brazil. 
Trinipap: Arima, Hitchcock 10310. 
Piarco Savanna, Hitchcock 
10363. St. Joseph, Hitchcock 
10177. Port of Spain, Hitch- 
cock 10320. Without locality, 
Bot. Gard. Herb. 3194. Fig. 149.—Distribution of P. hirtwm. 
bs : EXCLUDED SPECIES. 
The study of generssallied to Panicum and the examination of a 
large number of type specimens has resulted in the identification of 
most of the species of North America included now or in the past by 
some authors in Panicum. Besides the valid species and the names 
accounted for in synonymy within the genus Panicum there are a 
great many names that, according to our present conception of the 
genera of Paniceae, are referable to other genera. While the list is 
not complete it is so nearly complete as to enable us to account for 
almost all the names of North American species that have been re- 
ferred to Panicum. The second name in the column merely indicates 
the genus to which the species belongs. In no case is any name in 
the following list a transfer of a species or a new combination. In 
many cases the name, if transferred to the genus indicated, would 
be untenable. : 
