HITCHCOCK AND CHASE—NORTH AMERICAN PANICUM. 111 
Rachises bearing slender bristles (these wanting in 
exceptional specimens); blades broadest near 
the cordate or truncate base; nodes usually 
villous... 22.2... 2222-20 e ee eee eee eee eee 59. P. pilosum. 
Rachises without bristles; blades narrowed toward 
the base; nodes glabrous......... eee eee eeee 60. P. laxum. 
Panicle branches not racemose; blades scarcely wider 
than their sheaths; the sterile palea conspicuously 
enlarged. 
Spikelets 3 mm. long, congested; panicles dark pur- 
ple..... 2.22. eee eee eee eee eee eee eee 63. P. cupreum. 
Spikelets not over 2.4 mm. long; panicles green or 
pale. 
Panicle branches spikelet or branchlet-bearing 
along the upper half or toward the ends 
Only 2... eee ec eee eee eee 62. P. hians. 
Panicle branches branchlet- bearing throughout 
their length or nearly so..............--- 61. P. exiguiflorum. 
57. Panicum longum nom. nov. 
Panicum munitum Trin.; Steud. Nom. Bot. ed. 2. 2: 260. 1841. This nomen 
nudum is credited to ‘‘Trin. mpt. Mexico.”’ A specimen of P. longum collected 
near Jalapa by Schiede and Deppe, no. 674, and listed by Schlechtendahl@ as num- 
ber 898 ‘‘Panicum proximum piloso Sw.,’’ was examined at Halle. The sheet is 
marked ‘‘Panicum munitum” by Trinius, and may be the type of this name, but 
since the species was not described by Trinius P. longum is here based on Scribner’s 
type, Pringle 8195. 
Panicum pilosum macranthum Scribn. U. 8. Dept. Agr. Div. Agrost. Cire. 19: 1. 
1900, not P. macranthum Trin. 1826. ‘‘Swamps near Jalapa, State of Vera Cruz, 
altitude 1,230 m., May 21. C. G. Pringle, No. 8195. 1899.’’ The type, in the 
National Herbarium, is a slender plant 150 cm. high. 
DESCRIPTION. 
Plants perennial, ascending or spreading from a more or less geniculate base; culms 
rather robust, 1. 2 to 2 meters long, simple or sparingly branching from the lower nodes, 
glabrous, the nodes glabrous; sheaths nearly as long as the 
internodes or overlapping, papillose or papillose-hirsute 
(the greater number of papillz without hairs); ligule about 
0.5 mm. long; blades ascending or spreading, 10 to 25 cm, 
long, 6 to 12 mm. wide, linear, scarcely narrowed to the 
rounded base, very sparsely papillose-pilose on the upper 
surface, glabrous beneath or with a few papillee; panicles 
short-exserted or included at the base, 20 to 25 cm. long, 
. 2 to5 cm. wide, the branches raceme-like, the lower soli- 
Fie. 106.—P. longum. From tary, distant, the middle and upper opposite or verticillate, 
type specimen of P. pilosum the rachisesand upper part of the main axis with stiff hairs 
macranthum Scribn. . . . . 
slightly exceeding the short-pediceled, secund, approxi- 
mate, but scarcely crowded spikelets; spikelets mostly in pairs, 2.5 mm. long, 0.9 
mm. wide, pointed, strongly nerved, the nerves minutely scabrous toward the 
summit; first glume about half the length of the spikelet, pointed; second glume 
shorter than the sterile lemma, both slightly exceeding the fruit, the sterile palea 
@ Linnaea 6: 35. 1831. 
