176 



CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



Fig. 170.— P. neuranthum. From 

 type specimen. 



glabrous or with a few ciliae toward the base, the short basal blades few or wanting, 

 those of the middle culm usually 10 to 15 cm. (sometimes only 5 to 6 cm.) long, 3 to 5 

 mm. wide; panicles finally long-exserted, 5 to 9 cm. long, narrow, the flexuous branches 

 narrowly ascending, rarely loosely spreading, the branchlets appressed, the short- 



pediceled spikelets more or less secund along the 

 branches; spikelets 2 mm. long, 1.2 mm. wide, 

 broadly obovate, blunt, the attenuation at base 

 short; first glume about one-third the length of the 

 spikelet, truncate or pointed; second glume and 

 sterile lemma scarcely equaling the fruit at maturity, 

 finely papillose-pubescent; fruit 1.8 mm. long, 1.1 

 mm. wide, elliptic, puberulent at the subacute 

 apex. 



Autumnal form with erect, usually slender culms 

 nearly as tall as the vernal form; blades involute 

 but not stiff, not conspicuously shorter than the vernal blades, 4 to 10 cm. long; 

 spikelets more turgid, the fruit often slightly exceeding the second glume. 



Most nearly related to P. ovinum, from which the vernal form may be distinguished 

 by the narrower, fewer-flowered panicles with subsecund, slightly smaller spikelets, 

 by the usually taller culms, and by the absence of the comparatively broad basal blades 

 which distinguish the latter; the au- 

 tumnal form is much taller, with 

 longer, less crowded blades. From 

 P. aciculare this is distinguished by 

 absence of pubescence, much longer 

 blades, subsecund spikelets, and an 

 erect autumnal form. 



distribution". 



Fig. 171.— Distribution of P. neuranthum. 



Savannas and open ground, southern 

 Florida, and along the coast to Missis- 

 sippi; also in the Bahamas and Cuba. 



Florida: Miami, Hitchcock, 109, 705, 710; Alligator Harbor, Tracy 7176; Sanibel 

 Island, Simpson 298; Clearwater, Tracy 7166; Braidentown, Tracy 6711; 

 without locality, Rug el 290. 

 Mississippi: Petit Bois Island, Tracy 4567; Horn Island, Tracy 2859. 

 Bahamas: New Providence, Britton & Brace 599 (Field Mus. Herb.). 

 Cuba: Eastern Cuba, Wright 3453 in part. 



Bicknelliana. — Culms few to several in a tuft, glabrous or nearly so; sheaths glabrous 

 or with a few hairs; ligules nearly obsolete; blades somewhat elongated, 

 stiffly ascending or spreading, ciliate at base; panicles few-flowered, with 

 7-nerved, long-peduncled spikelets 2.5 to 3 mm. long. Autumnal form 

 sparingly branching from the upper or middle nodes. 



This group of two species is intermediate in habit between the Depauperata 

 and Dichotoma; the blades are elongated as in the former but the vernal 

 culms and the mode of branching are more like those of the latter. 



Spikelets 2.5 to 2.8 mm. long, blades not over 9 mm. wide 99. P. bicknellii. 



Spikelets 3 mm. long, blades as much as 12 mm. wide 100. P. calliphyllum. 



