Part 7 - UNC Herbarium

POACEAE 900
per node, loosely flowered; spikelets 4.7-7.7 mm long; first glumes 2.5-5.5 mm
long, 2/3-3/4 as long as the spikelet, 7-9 nerved, the nerves thickened and
raised; fertile lemma 1.3-1.8 mm wide ........................ P. amarum var. amarum
22 Rhizomes usually short; culms usually tufted, 1-2 (-3) m tall; leaves 2-5 dm
long; panicles 3-10 cm wide, the primary branches usually 2 or more per node,
densely flowered; spikelets 4.0-5.9 mm llong; first glumes 2-3.5 mm long, ½-
2/3 as long as the spikelet, 3-5 (-7) nerved, the nerves thin and wiry; fertile
lemma 1.0-1.5 mm wide ......................................................................................
..................................................................................P. amarum var. amarulum
21 Panicle with divergent to spreading-ascending branches; upper sheaths shorter than
internodes; spikelets 2.8-5 mm long; fertile lemma 2-2.6 mm long.
23 Spikelets 2.8-3.5 mm long; first glume 1/2 length of spikelet, blunt to acute ......
.....................................................................................P. virgatum var. cubense
23 Spikelets 3.5-5 mm long; first glume 2/3 length of spikelet, acuminate ..............
................................................................................... P. virgatum var. virgatum
17 Plants with hard crowns, lacking rhizomes; fertile lemma 1.2-1.6 mm long; [subgenus Agrostoides,
section Agrostoidea].
24 Ligule of white hairs 0.5-3 mm long; culms to 1 m long; cauline blades 2-8 mm wide, usually
pilose adaxially near the base; spikelets 2.0-4.0 mm long.
25 Ligules 1-3 mm long; spikelets 2.0-2.7 mm long, 2.5-4× as long as wide, often obliquely
set on the pedicels..............................................................P. longifolium var. longifolium
25 Ligules 0.5-1.5 mm long; spikelets 2.4-4.0 mm long, 3.5-5× as long as wide, erect on the
pedicels.................................................................................... P. longifolium var. combsii
24 Ligule a tawny membrane 0.5-1.0 mm long, often erose or lacerate, or with a minute ciliate
fringe; culms to 1.8 m long; cauline blades 4-12 mm wide, usually glabrous; spikelets 1.6-2.8
mm long.
26 Spikelets 2.4-2.8 mm long, long-acuminate, usually < 0.7 mm wide; fertile lemma often
conspicuously stipitate........................................................... P. rigidulum var. elongatum
26 Spikelets 1.6-2.5 mm long, short-acuminate, usually > 0.7 mm wide; fertile lemma
estipitate to short stipitate.
27 Culms to 1 m long; mature panicle ½ to nearly as wide as long, the branches
ascending to spreading; spikelets 1.6-2.2 mm long......... P. rigidulum var. rigidulum
27 Culms to 1.8 m long; mature panicle < 1/3 as wide as long, the branches erect;
spikelets 2.0-2.5 mm long.............................................P. rigidulum var. condensum
Panicum amarum Elliott var. amarulum (A.S. Hitchcock & Chase) P.G. Palmer, Southern Seabeach Grass. Cp (GA, NC,
SC, VA): coastal dunes and shores, sandflats, and sandhills; rare. July-November. NJ s. to FL and West Indies, w. to TX and
Mexico; restricted to the Coastal Plain except for WV. Although well-marked individuals of var. amarulum and var. amarum are
quite distinctive, only the number and structure of first glume nerves appears to be a constant over the range of the two taxa
(Palmer 1975). Primarily a coastal plant, var. amarulum has been found in the Sandhills of NC (Richmond Co.). Blomquist
1948 says this taxon "does not seem to grow naturally in North Carolina." [= K, Z; = P. amarulum A.S. Hitchcock & Chase –
RAB, C, F, G, HC, S; = P. amarum ssp. amarulum (A.S. Hitchcock & Chase) Freckmann & Lelong – FNA; not Panicum]
Panicum amarum Elliott var. amarum, Bitter Seabeach Grass. Cp (GA, NC, SC, VA): coastal dunes and shores; common.
August-November. CT s. to FL, w. to TX; restricted to the coast. See note under var. amarulum. [= K, Z; = P. amarum – RAB,
C, F, G, HC, S; = P. amarum ssp. amarum – FNA; not Panicum]
Panicum anceps Michaux var. anceps, Beaked Panic Grass. Mt, Pd, Cp (NC, SC, VA), {GA}: moist sandy woods,
swamps, sloughs, roadsides, fields, waste places; common. June-October. NJ w. to IL, s. to FL and TX. The sheaths of var.
anceps are glabrous to pilose, while those of var. rhizomatum are often villous; the leaves of var. rhizomatum also tend to be
hairier. [= RAB, F, G, Z; < P. anceps – C, GW, K, W; = P. anceps ssp. anceps – FNA; = P. anceps – HC, S; not Panicum]
Panicum anceps Michaux var. rhizomatum (A.S. Hitchcock & Chase) Fernald, Small Beaked Panic Grass. Cp (GA, NC,
SC, VA): moist to dry sandy or loamy pinelands, ditches; common (VA Watch List). July-October. Se. VA and KY s. to FL
and TX. See note under var. anceps. [= RAB, F, G, Z; < P. anceps – C, GW, K; = P. anceps ssp. rhizomatum (A.S. Hitchcock
& Chase) Freckmann & Lelong – FNA; = P. rhizomatum A.S. Hitchcock & Chase – HC, S; not Panicum]
Panicum capillare Linnaeus, Old-witch Grass, Tumbleweed, Tickle Grass. Mt, Pd (GA, NC, SC, VA), Cp (VA): open
sandy or stony soil, fields, roadsides, waste places, often weedy in cultivated soil; common (rare in SC). August-November. E.
to c. Canada, s. to FL and TX; Bermuda. Plants formerly known as P. capillare var. occidentale Rydberg, ranging from Canada
south to NJ, WV, KY, TX, and CA, are distinguished by long-acuminate spikelets 2.5-4 mm long that are mostly subsessile or
short-pedicelled. In our region, P. capillare has short-acuminate spikelets 1.8-2.8 mm long, mostly on long pedicels. [= RAB,
K, S, Z; < P. capillare – C, Y (also see P. gattingeri); > P. capillare var. capillare – F, HC, W; = P. capillare ssp. capillare –
FNA; = P. capillare var. agreste Gattinger – G; Panicum s.s.]
Panicum dichotomiflorum Michaux var. dichotomiflorum, Spreading Panic Grass, Fall Panic Grass. Mt, Pd, Cp (GA, NC,
SC, VA): marshy shores, exposed wet soils, alluvial deposits in floodplain forests, spoil banks, ditches; common. July-October.
E. Canada w. to SD, s. to FL and TX; also in the Bahamas (Sorrie & LeBlond 1997). P. dichotomiflorum var. puritanorum
ranges along the coast from s. NH to DE, and occurs inland in n. IN. It is distinguished by ovoid to ellipsoid, abruptly short-