HITCHCOCK AND CHASE—NORTH AMERICAN PANICUM. 71 
axillary from the upper 2 or 3 sheaths, rarely fascicled, approximate and forming an 
elongated inflorescence from two-thirds to almost the entire height of the plant, the 
individual panicles included at the base, 8 to 20 cm. long, half to two-thirds as wide, 
the slender, scabrous branches and branchlets and the long, flexuous pedicels divar- 
icate; spikelets 2.2 to 2.3 mm. long, 1.2 mm. wide, obovoid, turgid; first glume about 
half the length of the spikelet, acute; second glume and sterile lemma equal, slightly 
exceeding the fruit, abruptly short-pointed, strongly 5 to 7-nerved, the sterile palea 
about half the length of its lemma; fruit 1.7 mm. long, 1.1 mm. wide, oval, turgid. 
In its elongated inflorescence composed of several approximate panicles this species 
resembles P. rudgei Roem. & Schult., with which it has commonly been confused. 
DISTRIBUTION. 
Pine woods, Costa Rica, Cuba, and South America. 
Costa Rica: Buenos Aires, Tonduz 3685. 
Cusa: Pinar del Rio, Wright 3865; Ilerradura, Tracy 9073; Isle of Pines, Curtiss 
267, Palmer & Riley 1086, Taylor 34. 
Frencu Guiana: Cayenne (Paris Herb.). 
Brazit: Burchell 8350. 
Diffusa.— Perennials; culms stiff, somewhat tufted, sheaths mostly hirsute, ligules 
membranaceous, ciliate, 1 to 3 mm. long; blades long and narrow; spikelets 
mostly narrowly ovate, acuminate, glabrous; first glume clasping, the equal 
second glume and sterile lemma exceeding the fruit and pointed beyond it, 
the palea of the sterile floret about half as long as its lemma; fruit smooth and 
shining. The species of this group often resemble those of Capillaria, espe- 
cially in their spikelets, but the latter are all annual. 
Second glume and sterile lemma elongated, at least three 
times as long as the fruit..............--------------- 32. P. capillarioides. 
Second glume and sterile lemma not elongated. 
Panicles narrow, compact; blades 2 cm. or more wide... 38. P. hirsutum. 
Panicles diffuse, at least at maturity; blades not over 1 
cm. wide. 
Blades 1 to3 mm. wide, plants spreading or ascending 33. P. diffusum. 
Blades mostly over 5 mm. wide, plants erect. 
Spikelets 4 to 4.2 mm, long, the midnerves of 
glumes and sterile lemma scabrous toward 
the apex.........--..--2..----+--+------- 36. P. lepidulum. 
Spikelets usually less than 3.5 mm. long. 
Blades hirsute on both surfaces (sometimes 
clabrescent), not at all glaucous... ... 37. P. ghiesbreghtit. 
Blades glabrous on both surfaces or with a 
few hairs on either surface, glaucous 
above. 
Panicles much exceeding the leaves; 
spikelets 3 to 3.5 mm, (rarely 3.7 
mm.) long....------------+--+--++-- 35. P. hallit. 
Panicles usually equaled or exceeded by 
the uppermost blades; spikelets 2 
to 2.6 mm. long..........-.-.--- 34, 
a) 
. filipes. 
