Description: This native grass is a
summer annual that is tufted at the base with unbranched culms and basal
leaves. A typical tufted plant is about 8-12" tall and across with remnants of
dead leaves at its base; its culms are erect to widely spreading. The culms are
light green to purple, wiry, and often flattened; they are hairless to slightly
pubescent (with lines of short fine hairs that are difficult to see). Each culm
has up to 7 alternate leaves along its length. The blade of each alternate leaf
is about 2 cm. long and 1 mm. across; it is dull light green and hairless,
except for a few long hairs at its base. The basal leaves are a little longer
and wider, otherwise they are similar to the alternate leaves. The leaf sheaths
are light green, swollen, and hairless (or nearly so); they are shorter than
the internodes. Each culm terminates in a spike-like panicle that is up to
1½" (4 cm.) long; this panicle is exerted, in whole or part, from the
uppermost sheath. There are similar panicles contained with the sheaths
underneath; they are either completely hidden or only slightly exerted from
their sheaths. The side branches of each panicle are up to ½" long and
either erect or slightly spreading; these branches subdivide into branchlets
that each terminate in a single spikelet. A typical spikelet is about
4.0–4.5 mm. long, consisting of a pair of glumes, a lemma, and a palea
enclosing the perfect floret. Each glume is about 3.5–4.0 mm. long, linear
in shape, keeled, and hairless; one glume is usually slightly longer than the
other. The lemma and palea are 3.5–4.5 mm. long, linear-lanceolate in
shape, and keeled; they have fine hairs that are appressed and ascending. The
spikelets are pink, purple, or pale purplish green; they are often shiny. The
blooming period occurs during the early fall. Shortly afterwards, the foliage
and spikelets become light tan. There is a single grain per spikelet. The root
system is shallow and fibrous. This grass spreads by reseeding
itself.
Cultivation: The preference
is full sun, dry conditions, and barren soil containing sand or gravel. Most
vegetative growth occurs during the summer. The C4 metabolism of this grass
enables it to withstand drying winds and drought. It is unable to withstand
much competition from taller plants.
Range &
Habitat: Sheathed Dropseed is occasional throughout Illinois (see
Distribution
Map). Habitats include rocky openings in upland woodlands, dry sand
prairies, hill prairies, limestone and sandstone glades, fields and overgrazed
pastures, gravelly areas along roads and railroads, and barren waste areas.
This grass prefers disturbed areas with sparse ground vegetation. It is often
found in proximity to a similar species, Sporobolus neglectus (Small
Dropseed).
Faunal Associations:
Little is known about the floral-faunal relationships for this species. The
seeds may be eaten by the Mourning Dove, Field Sparrow, Tree Sparrow, and other
birds, particularly during the winter. This grass provides poor forage for
cattle and other livestock.
Photographic
Location: A gravelly area along a railroad in Champaign,
Illinois.
Comments: This is another
small weedy grass that is easily overlooked. Sheathed Dropseed is very similar
in appearance to Sporobolus neglectus (Small Dropseed), except that it
has longer glumes and lemmas (about 4 mm. in length). In contrast, Small
Dropseed has glumes and lemmas that are about 2 mm. in length and they are less
slender and pointed. Both of these grass species bloom late in the year and
they both produce spike-like inflorescences that are partially or totally
hidden by their sheaths. Other Sporobolus spp. (Dropseed Grasses) with
such inflorescences are larger perennial grasses; their narrow panicles are at
least 5 cm. (2") in length. Other common names of Sporobolus
vaginiflorus are Sheathed Rush Grass and Poverty
Grass.