Description: This native grass is a
summer annual. In open areas, it forms a large tuft of foliage spanning about
2' across and 1½' high. In areas with dense vegetation, it is more erect
and about 2-3' tall. The culms are often decumbent near the base, where they
often form rootlets along the lower nodes. The culms are terete, glabrous, and
branched; they are variably colored, including bone white, light green, or
light reddish green. The blades of the alternate leaves are up to 8" long and 5
mm. across; they are medium green, rough-textured, and ascending to widely
spreading. The sheaths are medium green, hairless, and rather loose. At the
junction of each sheath and blade, the ligule consists of a papery membrane at
least 3-5 mm. long. The nodes along each culm are dull and dark-colored. The
culms terminate in panicles of spikelets. The typical panicle is about 8" long
and 3½" across; it consists of a central stalk (rachis) with several
lateral stalks (rachillae). Both the central and lateral stalks are stiff,
rough-textured, and straight. The lateral stalks originate from the central
stalk in pairs or individually; they are up to 3½" long and ascending.
Many appressed spikelets occur along the length of each lateral stalk; they are
nearly sessile. Each spikelet is about 7-11 mm. long, 2 mm. across, and
somewhat flattened; it has of a pair of glumes (at the bottom) and 5-10 lemmas
that are organized into 2 columnar ranks. The glumes are linear-lanceolate to
lanceolate with green midveins along their keels; one glume is about 2 mm.
long, while the other is about 3 mm. long. The lemmas are linear-lanceolate to
lanceolate and about 4-5 mm. long; each lemma has a green midvein on its keel,
2 green lateral veins, and a slightly awned tip (less than 1 mm. in length).
Each lemma encloses a palea with a perfect floret. The blooming period occurs
from mid-summer to early fall. Cross-pollination is by wind. Each grain is
about 2 mm. long, ovoid, and flattened. The root system is fibrous. This grass
reproduces by reseeding itself.
Cultivation: The preference is full sun, wet to
moist conditions, and rather sterile soil that is alkaline and/or salty. The C4
metabolism of this grass enables it to withstand hot weather and occasional
droughts.
Range & Habitat:
Bearded Sprangletop is occasional in the southern half of Illinois, and
uncommon or absent in the northern half of the state (see
Distribution
Map). At one time, this species was uncommon and largely restricted to SW
Illinois, but it has become more common and is spreading into new areas.
Habitats include soggy thin woodlands, disturbed areas of marshes, sand flats,
roadside ditches, and low gravelly areas along railroads. This grass flourishes
in low areas where road salt accumulates; it also likes low areas where
limestone gravel is present. In the Great Plains and western states, this grass
can be found in brackish marshes. In Illinois, this species is more common in
disturbed areas.
Faunal
Associations: Little information is available about floral-faunal
relationships for this species. A polyphagous insect, Melanoplus
sanguinipes (Migratory Grasshopper), eats the foliage of Leptochloa
spp. (Sprangletop Grasses) and many other species of grasses. In marshes
and other wetlands, the Green-Winged Teal, Blue-Winged Teal, Mallard, and other
dabbling ducks eat the seeds of Bearded Sprangletop. I suspect that the
Mourning Dove and many sparrows feed on the seeds of this grass occasionally
when it occurs along railroads and roadsides.
Photographic Location: A low gravelly area along a
railroad in Champaign, Illinois.
Comments: Bearded Sprangletop is a rather
weedy-looking grass that likes to sprawl across open ground. However, its stiff
inflorescence is held more or less erect. This grass is very similar in
appearance to a more western species, Leptochloa acuminata (Salt Meadow
Grass). The latter species has larger glumes and its foliage is even more
rough-textured. Some authorities consider these two grasses to be variants of
the same species. Other Leptochloa spp. (Sprangletop Grasses) are
perennials; they have spikelets that lack awns and their glumes and lemmas are
shorter in length. These species also occur in wetlands, primarily in southern
Illinois.