Description: This adventive grass is a summer annual
about ½–2' tall that is tufted at the base; its culms branch
occasionally. The lower culms are decumbent, while the upper culms are
ascending to spreading.
Each slender culm is terete, glabrous,
and pale green to pale purple. The blades of the alternate leaves are up to 4"
long and 1/3" across; they are light to medium green or blue-green, rather
flat, and mostly hairless; sometimes there are scattered white hairs toward the
base of the blades. The inflated sheaths of the leaves cover most of the culms;
these sheaths are finely veined, hairless, and the same color as the blades.
The upper culms terminate in digitate clusters of 2-6 racemes. These racemes
are very narrow, spike-like, and up to 5" long. Each raceme has 2 rows of
spikelets and a flattened central stalk (or rachis) about 1 mm. across. These
spikelets occur in pairs or individually along the racemes on very short
pedicels. Each spikelet is about 2 mm. long, dark green or purplish green,
ellipsoid or ovoid in shape, and flattened; it consists of a pair of glumes, a
pair of lemmas, and a single floret. The outer sides of the spikelet consist of
the 2nd glume and the outer lemma; the 1st glume is small and insignificant,
while the inner lemma is dark-colored and hidden from view. The blooming period
occurs from mid-summer into the fall. Pollination is by wind. The small seeds
are ellipsoid or ovoid and flattened. The root system is shallow and fibrous.
This grass reproduces primarily by reseeding itself, although it can spread
vegetatively by forming rootlets at the lower nodes of its
culms.