Plants annual; tufted. Culms to 60 cm,
often prostrate and branching at the base, glabrous; internodes solid. Sheaths open
or closed, rounded on the back, frequently hispid; auricles absent; ligules membranous,
usually lacerate and minutely ciliate; blades flat, mostly ascending,
glabrous or hispid abaxially and/or adaxially. Inflorescences panicles,
loosely contracted; branches spikelet-bearing to the base or
nearly so. Spikelets pedicellate, subterete, with 1 floret; rachillas prolonged
as a slender bristle, glabrous; disarticulation below the glumes. Glumes equal,
rigid, chartaceous, hispid or scabrous, veinless or obscurely 3-5-veined,
acute, unawned; calluses blunt, glabrous; lemmas equaling
the glumes, chartaceous, smooth, veinless or inconspicuously 3-veined,
minutely bifid or acute, awned near the apices, awns exceeding the
florets, geniculate near midlength, basal segment twisted; paleas shorter
than the lemmas, veinless or the base 2-veined, hyaline; lodicules 2,
glabrous, toothed or not toothed; anthers 3; ovaries glabrous. Caryopses about
2.5 mm, linear. x = 7. Name from Limnas, a similar Eurasian
genus, and the Greek odes, like.
Limnodea is a monotypic genus of the southern United States and adjacent Mexico.
1. Limnodea arkansana (Nutt.) L.H. Dewey
Culms 15-60 cm. Ligules 1-2 mm; blades 3-12 cm long, 2-8 mm wide. Panicles 5-12 cm long, 1-5 cm wide, loose, mostly erect. Spikelets 3-4 mm; rachillas prolonged 0.3-0.9 mm. Glumes 3-4 mm; lemmas 3-4 mm, awns (5)8-14.5 mm; anthers 0.2-0.4 mm. 2n = 14.
Limnodea arkansana grows in dry, usually sandy soils of prairies, open woodlands, disturbed areas, and riverbanks. Along the Gulf coast, it grows on maritime shell mounds and middens and upper beaches where shells accumulate. It has also been found, as an introduction, around a wool-combing mill in Jamestown, South Carolina.