HITCHCOCK AND CHASE—-NORTH AMERICAN PANICUM. AL 
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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; Herradura, Tracy 9073; Isle of Pines, Curtiss 
267, Palmer & Riley 1086, Taylor 34. 
Frencu Guiana: Cayenne (Paris Herb.). 
Braziu: 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 
immesiag loneras the truths soe ky ee ek ss 32. P. capillarioides. 
Second glume and sterile lemma not elongated. 
ves 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.to 3mm. 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 
BOYS); BOXED. ea RE ies oes EMAC ea ee Rl . 36. P. lepidulum. 
Spikelets usually less than 3.5 mm. long. 
Blades hirsute on both surfaces (sometimes 
glabrescent), not at all glaucous.-.... 37. P. ghiesbreghtii. 
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 
rein Nae.) (Gye Kerta(ee Mpsee Ns ace Ned nO AUN 35. P. halir. 
Panicles usually equaled or exceeded by 
the uppermost blades; spikelets 2 
Wo) elo) sogutole Movavers ey Ga ery ee 34. 
y 
. filipes. 
