4. Scleria reticularis Michx. var.
pubescens Britton (Muhlenberg’s nut grass)
Pl. 87 d, e; Map 329
S. muhlenbergii Steud.
Plants perennial, sometimes with very short
rhizomes (annual elsewhere). Aerial stems 15–80 cm long, clustered, erect to
spreading, sometimes flattened somewhat near the tip, glabrous or rarely
sparsely hairy. Leaf sheaths often narrowly winged or roughened along the
angles, glabrous or nearly so, green or tinged with purple in the basal half,
the convex tip opposite the leaf blade 2–3 mm long, broadly rounded, hairy or
glabrous. Leaf blades 1–30 cm long, 2–5(–8) mm wide, glabrous or sparsely
hairy, the margins and main veins sometimes roughened. Inflorescences few to
several loose clusters of spikelets, these arranged in a short panicle. Bracts
erect to ascending, 0.7–4.0 cm long. Spikelets 2–4 mm long, the scales green to
straw-colored or purplish tinged. Fruits with the main body 1.5–2.5 mm long at
maturity, broadly ovate to nearly circular in outline, the tip with a minute
point, the surface with a complex, netlike or honeycomb-like pattern of ridges
and often also with horizontal wrinkles; minutely hairy, usually in patches,
dull, white to light gray, the basal disk strongly 3-lobed, lacking tubercles,
the lobes appressed to the base of the main body of the fruit. August–October.
Uncommon in the southern portion of the
Ozarks (eastern U.S. west to Wisconsin and Texas; Mexico, Central America,
South America, Caribbean Islands). Mesic upland and bottomland prairies,
especially along watercourses.
This species is widespread in the New World
but known from few collections in Missouri. The stems tend to be more slender
than those of the superficially similar S. triglomerata and are
frequently somewhat lax and supported by other vegetation. The inflorescences
are relatively loosely flowered, with the spikelets in more of a panicle than a
headlike cluster. When produced, axillary inflorescences are usually on long,
slender stalks that arch or droop. Although all of the Missouri specimens
collected to date have hairy fruits, elsewhere plants produce fruits that range
from densely hairy to totally glabrous. The unusual 3-lobed, “calyx-like” basal
disk is a more stable character for this species’ determination than the
pubescence of the fruits.