HITCHCOCK AND CHiASE NORTH AMERICAN PANICUM. 221 



agrees with these specimens except that the spikelets are said to be glabrous. But 

 this statement is probably an error of observation or of description, since the author 

 adds, "Related to Panicum lanuginosum Ell., and separated from it by having a 

 longer, softer pubescence and its leaves not being ciliate." Since the spikelets of 

 P. lanuginosum as described by Ashe (P. huachucae silvicola) are pubescent, this dif- 

 ference would probably have been noted in the contrast of the two species. A por- 

 tion of the specimen mentioned above has been deposited in the National Herbarium 

 and has been chosen as the type of P. orangense Ashe. It is the early autumnal form. 

 Panicum ciliosum Nash, Bull. Torrey Club 26: 568. 1899. "Type collected by 

 S. M. Tracy, at Biloxi, Mississippi, September 1, 1898, no. 4580." The type, in 

 Nash's herbarium, is the early autumnal form with a simple culm and primary panicle 

 attached, and without the winter rosette. The specimen of Tracy 4580 in the National 

 Herbarium has a winter rosette, the blades 4 to 6 cm. long. In the description the 

 ligule is said to be "about 0.5 mm. long " but in the type it measures 3 mm. long. 



DESCRIPTION. 



Vernal form grayish olive green, velvety to the touch; culms tufted, usually in 

 large clumps, 40 to 70 cm. long, slender, lax, spreading, densely villous with fine, 

 soft hairs arising from small papillae; nodes villous, often a glabrous ring below; 

 sheaths shorter than the internodes, soft-villous like the culm, or the upper puberulent 

 only, ciliate on the margin; ligules 3 to 4 mm. long; blades thickish but not stiff, 

 ascending or spreading, somewhat incurved or spoon-shaped, 5 to 10 cm. long, 5 to 10 

 mm. wide (the uppermost much smaller), acuminate, narrowed toward the rounded 

 base, the margins sometimes papillose-ciliate, the upper surface clothed with short, 

 soft hairs with long soft hairs intermixed, especially toward the margins and base, the 

 lower surface densely velvety-pubescent; panicles exserted, 6 to 12 cm. long, about 

 as wide, loosely flowered, the axis pubescent, the slender flexuous branches spreading 

 or ascending, the lower often drooping; spikelets 1.8 to 1.9 mm. long, 1 mm. wide, 

 obovate-elliptic, subobtuse, pubescent; first glume one-third the length of the spike- 

 let, obtuse or obscurely pointed; second glume and 

 sterile lemma equal, slightly shorter than the fruit 

 at maturity; fruit 1.6 mm. long, 0.9 mm. wide, ellip- 

 tic, subacute. 



Autumnal form widely spreading or decumbent, 

 freely branching from the middle nodes, the branches 

 repeatedly branching and much exceeding the 



internodes, the ultimate branchlets forming flabel- 

 FiG. 227.— P. lanuginosum. From i,j--ii j • ■, i,jj 



t r)e specimen ^^^ fascicles; leaves and panicles much reduced, 



the flat blades almost always ciliate and exceeding 



the panicles; winter rosette not appearing until late, the blades 4 to 5 cm. long, 



usually ciliate, otherwise minutely velvety or nearly glabrous. 



The plant bears some resemblance in color and pubescence to P. scoparium, but is 

 smaller and much more slender. The vernal form also resembles P. huachucae silvicola 

 but is larger and more velvety and is gray-green in color rather than bright green. 



It may be that the form described by Nash as P. ciliosum is a distinct species. 

 It differs in having blades glabrous on the upper surface or with a few long hairs only, 

 but not velvety, and winter rosettes of large blades. The typical form has been found 

 only in Tracy's garden, at Biloxi, in cultivated soil. Other Biloxi specimens lack 

 the large rosettes, probably because not growing in cultivated soil. The following 

 specimens, because of the lack of velvety pubescence on the upper surface of the 

 blades, may be referred to this form: Mississippi: Biloxi, Chase 4331, Hitchcock 

 1079, Traaj 1735, 2867, 3620, 3622, 3645, 4580, 4605; Ocean Springs, Tracy 6469. 

 Louisiana: Lake Charles, Hitchcock 1152, Chase 4401. 



