keys to the vascular plants of east texas - Botanical Research ...

984 POACEAE/MUHLENBERGIA
Bandera, Edwards, and Kerr (Denny 2003) cos. on the Edwards Plateau; AZ, NM, and TX. Sep–
Nov. According to Peterson (2003b), this species “resembles M. rigens, but differs in having
looser, contracted (but not spikelike) panicles, longer ligules, olivaceous anthers, and generally
longer lemmas.”
Muhlenbergia expansa (Poir.) Trin., (expanded), SAVANNAH HAIR GRASS, CUTOVER MUHLY. Tufted
perennial without rhizomes, similar to M. capillaris; culms erect, 60–100(–150) cm tall; leaf
sheaths rounded, the basal ones often very fibrous or sometimes not so; ligule ca. 2–5(–10) mm
long; panicles open, diffuse; spikelets 3–5 mm long; glume body 1/2–2/3 as long as lemma
body; upper glume awnless or with minute awn; lemma without setaceous teeth, usually awnless
or with an awn 3 mm or less long. Moist to wet pine forests, savannahs, bogs, sandy soils;
Hardin (MacRoberts & MacRoberts 3724, SBSC), Jasper, Newton (Peterson 2003b), and Liberty
(Gould 1975b) cos.; e U.S. from NC s to FL w to OK and TX. Aug–Oct. [Agrostis trichopodes Elliott,
M. capillaris (Lam.) Trin. var. trichopodes (Elliott) Vasey] Gould (1975b) treated this taxon
as M. expansa and commented that it has “characters sufficiently distinct to warrant specific
recognition.” Morden and Hatch (1989), however, concluded that there is overlap with M.
capillaris in supposedly diagnostic characters and that “there is no clear separation of taxa”;
they therefore treated the taxon as M. capillaris var. trichopodes. Jones et al. (1997), Peterson
(2000), and Hatch (2002) recently recognized M. expansa, as did Peterson (2003b) in his Flora
of North America treatment.
Muhlenbergia frondosa (Poir.) Fernald, (leafy), WIRE-STEM MUHLY, NIMBLE-WILL, SATIN GRASS. Rhizomatous
perennial; culms often becoming decumbent or sprawling, to 100(–130) cm long; leaf
sheaths rounded to slightly angled; ligule 0.7–1.4(–1.7) mm long; panicles numerous, slender;
spikelets 2.3–4.1 mm long; lemma basally pubescent, awnless (in TX material—Correll &
Johnston 1970; awned elsewhere in the species range—see e.g., Yatskievych 1999; Peterson
2003b). Woods, clay soils; in TX reported only from Dallas and Grayson (Correll & Johnston
1970) cos. at w margin of East TX; however, we have seen no TX material of this species and its
status in TX is unclear; se Canada and e U.S. w to ND and TX, also OR. Oct. While not officially
designated as such (e.g., TOES 1993; Carr 2002d; Poole et al. 2002), given its limited distribution
in the state, we consider this species to be of conservation concern in TX. �
Muhlenbergia glabriflora Scribn., (smooth-flowered), INLAND MUHLY, SMOOTH MUHLY. Rhizomatous
perennial similar to M. frondosa; leaf sheaths rounded to slightly angled; ligule 1.5 mm or
less long; panicles numerous, slender; spikelets 2–3.5 mm long; lemma glabrous, including at
base, usually awnless. Moist woods, clay soils, Dallas Co. (BRIT; Peterson 2003b), in TX known
only from the Blackland Prairie, the type of this species was collected by Reverchon in Dallas
(Mahler 1988); c U.S. from IN s to LA w to MO and TX. Sep. This species is similar to M. frondosa
but can be distinguished by the glabrous lemmas, shorter fruits (1.2–1.4 mm long), and culms
puberulent below the nodes (versus lemmas pubescent basally, fruits 1.6–1.9 mm long, and
culms glabrous in M. frondosa). This is one of a group of somewhat similar species (others are
M. bushii, M. frondosa, M. sobolifera, and M. sylvatica) that are rather rare in East TX, whose relationships
are unclear, and that are in need of study. While not officially designated as such
(e.g., TOES 1993; Carr 2002d; Poole et al. 2002), given its limited distribution in the state, we consider
this species to be of conservation concern in TX. �
Muhlenbergia �involuta Swallen [M. lindheimeri � M. reverchonii], (rolled inward), CANYON
MUHLY. Densely tufted perennial without rhizomes; culms stiffly erect, 60–140 cm tall; leaf
sheaths keeled; ligule 3–12 mm long; panicles ca. 18–40 cm long, open but branches only narrowly
spreading; spikelets 3–4 mm long; lemma 3–4 mm long, minutely bifid apically, with
awn 0.5–2(–4) mm long from between the minute apical teeth. Prairie draws and openings, calcareous
slopes, and canyons; Hays, Travis (BRIT), Bexar (Turner et al. 2003), and Comal (Mahler
1988) cos. on sw margin of East TX; mainly Edwards Plateau, also s margin of Cross Timbers