32 
mostly longer than the internodes, ligule ubsolete; panicle oblong, rachis zigzag, 1 
inch jong; lower branches subverticillate, short; spikelets about 1} lines long, pubes- 
cent; lower glume ovate, one-fourth as long as the spikelet; second and third glumes 
with 5 to 7 broad nerves, the third hardly as long asthe flowering glume.—Nebraska 
(Dr. T. E. Wiicov). Perhaps a depauperate form of the preceding. 
41. P. spherocarpon Ell. (Chapm. FI., 8. States, Suppl. p. 667.) Culms 15 to 
24 inches long, 5 to 7 lines wide, lanceolate, acute, obscurely nerved, smooth except at 
the ciliate-cordate base; sheaths shorter than the joints, smooth ; panicle 3 to 4 inches 
long, spreading; spikelets oval, five-eighths to three-fourths of a line long, smoothish 
lower glume one-third as long as the spikelet.—Dry or moist ground, of same range 
as the next species. Differs from P. dichotomum in its wider, more rigid, smooth, pale 
leaves, with cordate base. 
Var. FLORIDANUM. Culms J} to 24 feet high, rigidly erect; leaves rigid, erect, 6 
to 7 on the culm, lanceolate, smooth, about 3 inches long, 5 to 6 lines wide, the 
margins near the base, and sheaths ciliate ; panicle oval to oblong, 3 to 5inches long, 
and spikelets one-half line long, pubescent, the ower glume } or } as long as the 
spikelet.—Florida. 
Described by Dr. Chapman as P, spherocarpon Ell, but it hardly agrees with Elli- 
ott’s description. It is intermediate between P. microcarpon and P. spherocarpon. 
42, P. microcarpon Muhl. (Gray’s Manual, 6th ed., p. 633.) (P. multiflorum EI1.) 
Culms 2 to 3 feet high, stout, erect, smooth: leaves 4 to7 inches long, 9 to 12 lines wide, 
lanceolate, gradually tapering to a slender point, with nine to eleven nerves, rough- 
ish above and on the margin, sometimes bristly-ciliate at the rounded, clasping base, 
smooth on the under side, sheaths mostly longer than the internodes, smooth except 
on the margins; ligule nearly obsolete, panicle becoming long-peduncled, 3 to 7 
inches long, 1 to 2 inches broad, spreading, multiflorous, branches mostly verticillate, 
very numerous, flowering to the base, spikelets mostly long-pediceled, oval, five- 
eighths of a line long, nearly smooth, lower glume one-fourth as long as spikelet, sec- 
ond glume 7-nerved.—Low ground, Massachusetts to Texas. 
43. P. viscidum Ell. (Gray’s Manual, 6th ed., p. 632.) Culms 2 to4 feet high, stout, 
becoming much branched, leafy, velvety-downy all over, except a narrow ring below 
each node; sheaths suft-downy, the hairs spreading or reflexed and often viscid, 
leaves downy or smoothish, lanceolate, 4 to 8 inches long, diffuse, the branches 
numerous and much subdivided, spikelets fully 1 line long, oblong-obovate, pubes- 
cent, lower glume one-fourth to one-fifth as long as the 7- to 9-nerved upper one.— 
Common. 
44, P. commutatum Schultes, (Chapm. FI, 8. States, Suppl. p. 667.) (2D. nervo- 
sum Muhl.) Culms 2 to 2} feet long, erect, unbranched, rather slender, smooth; leaves 
at the base rigid, ovate-lanceolate, the three or four culm leaves firm but not rigid, 
mostly 3 to 4 inches long, 8to 12 lines wide, acuminate, cordate at base, smooth except 
on the margins, sheaths smooth or somewhat pubescent, much shorter than the 
nodes; panicle peduncled, 3 to 5 inches long, 2 to 3 inches wide, open, rather thin, 
branches smooth, single or subverticillate ; spikelets rather long-pediceled, oblong, 
sparsely hairy, 1 to 1} lines long; lower glumes one-third as long as the spikelet, sec- 
ond about 5- and third 7-nerved.—Pennsylvania to Texas, A fine species, in appear- 
ance like P. clandestinum, but more slender, with shorter leaves and smaller spikelets, 
which are early deciduous. 
Var. MINOR, differs from the preceding in its rather smaller size (14 to 2 feet), 
and smaller panicle, and the spikelets more persistent.—Southern States. 
45. P.clandestinum Linn. (Gray’s Manual, 6th ed., p. 632.) Culmsrigid, 2 to 3 feet 
high, leafy to the top, rarely branched, upper nodes smooth, the lower often hairy; 
sheaths smoothish, or the lower ones often rough with papillose, bristly hairs, shorter 
than the internodes, leaves large, lanceolate to oblong-lanceolate, 4 to 8 inches long, 9 
to 15 lines wide, with a cordate, clasping base, very taper-pointed, smooth except the 
tough margins; panicle at first partially sheathed, becoming long-pedunculate, some- 
