HITCHCOCK AND CHASE—TROPICAL NORTH AMERICAN PANICUM. 527 
110. Panicum chiriquiense sp. nov. 
DESCRIPTION. 
Plants perennial, olivaceous; culms straggling, creeping and rooting at the lower 
nodes, softly papillose-pilose, freely branching, the leafy fertile branches ascending, 
20 to 30 cm. high; nodes pilose; sheaths nearly as long as the internodes or the upper 
overlapping, softly papillose-pilose; ligule about 0.5 mm. long; blades flat, somewhat 
spreading, 4 to 7 cm. long, 7 to 10 mm, wide, nar- 
rowly lanceolate, unsymmetrical at base and often 
somewhat falcate, acuminate, softly papillose- 
villous beneath, rather sparsely pilose on the 
upper surface; panicles short-exserted or included 
at base, 2.5 to 3.5 cm. long, half to two-thirds as 
wide, the few branches ascending, the axis and 
few nearly simple branches slender, villous; spike- 
lets short-pediceled, 2.6 to 2.8 mm, long, about 
1.1 mm. wide, elliptical; first glume about three- 
fourths as long as the spikelet, acute, 3-nerved, Fig. 138.—P. chiriquiense. From 
villous; second glume and sterile lemma equal, type specimen. 
covering the fruit, the glume villous, minutely 
apiculate, the lemma usually subindurate, smooth and shining in the two middle 
internerves, the midnerve suppressed or evident at the summit only, the lateral 
internerves villous; fruit 2.1 mm. long, 1 mm, wide, minutely apiculate. 
Type in the U. 8. National Herbarium, no. 725186, collected ‘“‘in shade along 
trail, hillside jungle, foothills, vicinity of El Boquete, province of Chiriquf, Panama, 
altitude 1,000 to 1,300 meters, October 4, 
1911,” by A. 8. Hitchcock (no. 8313). 
Known only from the type collec- 
tion. This species differs from P. cor- 
dovense in the villous foliage with 
shorter, unsymmetrical blades, the 
less elongate culms, and the smaller 
spikelets. In the specimens collected 
all the panicles are terminal on the 
branches. Whether or not the plants 
Fig. 139.—Distribution of P. chiriquiense. at an earlier season bear large panicles 
on a primary culm is not known. The character of the suppressed midnerve and 
smooth middle internerves, rare in P. cordovense, is usual and emphazised in P. chiri- 
quiense. Only an occasional spikelet in panicles with the usual form has undiffer- 
entiated middle internerves. 
MISCELLANEOUS SPECIES. 
111. Panicum obtusum H. B. K. 
Panicum obtusum H. B. K. Nov. Gen. & Sp. 1: 98, 1816; Contr. U. 8. Nat. Herb. 
15: 321. 1910. 
DISTRIBUTION. 
Moist sandy or gravelly soil, southwestern United States to central Mexico. The 
type specimen from Guanajuato. 
Sonora: Nogales to Cocospora Ranch, Griffiths 6800. 
CurmvuaHua: Between Casas Grandes and Sabinal, Nelson 6352. Chihuahua, 
Pringle 476. Mifiaca, Hitchcock 7734. 
