Part 7 - UNC Herbarium

POACEAE 895
5 Glumes minute, 0-0.5 mm long; plant lacking rhizomes; culms weak, decumbent and cespitosely branching in their
lower portions, rooting at the nodes, the upper portions erect and sparsely branched.....................................M. schreberi
5 Glumes well-developed, 1-7 mm long; plant with scaly rhizomes (except for M. cuspidata); culms firm (rarely
sprawling), few or solitary (rarely forming dense colonies).
6 Glumes 5-7 mm long (tapered to arched or straight awns), about double the length of the lemma (excluding its
awn); panicle dense and spike-like, 2-6 cm long and 3-10 mm broad................................................... M. glomerata
6 Glumes 1.2-3 mm long, shorter than to barely exceeding the lemma; panicle usually slender, arching, generally
less dense and not spike-like, often with some elongated (though appressed) branches, 4-50 cm long, 2-15 mm
broad.
7 Callus glabrous; plant lacking scaly rhizomes (with slender stolons and a hard, knotty crown); leaves 0.5-2
mm wide; [of calcareous cliffs]...................................................................................................... M. cuspidata
7 Callus bearded (sometimes only slightly so) (glabrous in M. glabriflora); plant with scaly rhizomes; leaves
(1-) 2-14 mm wide; [collectively of various habitats].
8 Panicle linear, loosely flowered, much exceeding the leaves; culm erect, simple or sparingly branched;
glumes relatively broad, the body ovate, 1.2-2.5 mm long, abruptly narrowed to the acuminate tip; ligule
obsolete or shorter than the elongate cartilaginous summit of the leaf sheath.
9 Lemmas awnless or awn < 0.5 mm long; spikelets 1.5-2.5 mm long; leaf blades usually (1-) 2-6
mm wide.........................................................................................................................M. sobolifera
9 Lemma awn 1-11 mm long (rarely awnless); spikelets 3-5 mm long; leaf blades (2) 6-10 (-13) mm
wide (often > 8 mm wide) ..............................................................................................M. tenuiflora
8 Panicle lanceolate, densely (rarely loosely) flowered, leaves often extending conspicuously into the
inflorescence; culm geniculate, freely branched; glumes relatively narrow, the body lanceolate, 2-3 mm
long, tapering from base to apex; ligule usually obvious above the short cartilaginous summit of the leaf
sheath.
10 Culm glabrous throughout (including below the nodes).
11 Glumes 1.4-2.0 mm long; ligule 0.2-0.5 mm long........................................................M. bushii
11 Glumes 2-4 (-5) mm long; ligule 0.8-1.5 mm long.................................................. M. frondosa
10 Culm pubescent, at least below the nodes.
12 Lemma awn 7-12 mm long; spikelets loosely clustered, on pedicels 2-4 mm long.....................
..................................................................................................................................M. sylvatica
12 Lemma awnless or with a short awn tip (rarely to 9 mm long); spikelets densely clustered, on
pedicels < 1 mm long.
13 Lemma glabrous below, or with short basal bearding; ligule 0.5-1.5 mm long ...................
......................................................................................................................M. glabrifloris
13 Lemma pilose basally; ligule 0.5-1 mm long.................................................. M. mexicana
Muhlenbergia bushii Pohl, Bush's Muhly. Pd (VA), Mt (GA), {NC}: bottomlands and other moist forests; rare (VA Rare).
IN west IA, south to NE and TX; apparently disjunct eastward in scattered localities, including in n. GA (Jones & Coile 1988)
and VA. The habitat is variously given in floras as "dry woods" or "moist woods." [= C, FNA, K; = M. brachyphylla Bush – F,
G, HC]
Muhlenbergia capillaris (Lamarck) Trinius, Hairgrass. Pd, Cp (GA, NC, SC, VA), Mt (GA, NC, VA): in the Piedmont
primarily in clayey or thin rocky soils (especially in areas which formerly burned and were prairie-like), open woodlands, in the
Coastal Plain in savannas, dry woodlands, and coastal grasslands (where sometimes in close proximity with M. sericea), in the
mountains around calcareous rock outcrops; uncommon. Late August-October. The species is widespread in e. North America.
M. capillaris and its relatives, M. expansa and M. sericea, have been the subject of an herbarium morphological study by Morden
& Hatch (1989), who conclude that the three taxa are not sharply separable and should be recognized only at the varietal level. If
one considers behavior in the field, ecology, and geography in conjunction with morphologic characters, however, there is little
doubt that the three taxa are biological species. Distribution and typical habitat are different for the three species, but M.
capillaris can be found growing with or in proximity to each of the other two (I have not seen M. sericea and M. expansa
together). In such situations, the two taxa present are readily distinguishable at a glance, and there is no evidence of
intermediates or hybrids. [= F, FNA, G, W; < M. capillaris – RAB, GW (also see M. sericea); = M. capillaris var. capillaris –
C, HC, K, S]
Muhlenbergia cuspidata (Torrey ex Hooker) Rydberg, Plains Muhly. Mt (VA): dolomite and limestone palisade cliffs
along the New, Roanoke, and Shenandoah rivers; rare (VA Rare). OH west to MT and Alberta, south to sw. VA, KY, MO, OK,
and NM. [= C, F, FNA, G, HC, K]
Muhlenbergia expansa (Poiret) Trinius, Savanna Hairgrass. Cp (GA, NC, SC, VA): pine savannas, pine flatwoods, mesic
areas in sandhill-pocosin ecotones; common (VA Rare). September-October. An important part of the grassy component of
many longleaf pine savannas, M. expansa is a Coastal Plain species, ranging from se. VA south to FL, and west to e. TX (nearly
exactly the range of Pinus palustris). Its flowering is stimulated by fire, and, lacking fire, it may be found in large populations in
solely vegetative condition. It can be distinguished in sterile condition from other savanna bunchgrasses (Sporobolus teretifolius,
S. pinetorum, S. floridanus, S. curtissii, Aristida stricta, and A. beyrichiana) by the following characteristics: old leaf bases
fibrous and curly (rather than hardened and cartilaginous), ligules 1-3 mm long (rather than 0.2 to 0.5 mm long). The open
panicle somewhat resembles that of several species of similar habitat which often co-occur with M. expansa – Sporobolus
teretifolius, S. pinetorum, S. curtissii, S. floridanus, and Calamovilfa brevipilis, but the panicle of M. expansa is capillary,