Plants grayish-green, cespitose, with caudices. Basal
rosettes poorly differentiated; blades usually large, ovate to lanceolate,
often transitional to the cauline blades. Culms 15-75 cm, erect; nodes
glabrous or sparsely pubescent; internodes glabrous or puberulent to pilose
basally; fall phase with erect to spreading culms, extensively branched
from the mid- and upper culm nodes, eventually producing flabellate clusters
of reduced, flat or involute blades. Cauline leaves 3-7; sheaths
shorter than the internodes, glabrous or with soft, ascending, papillose-based
hairs; ligules 0.5-2 mm, of hairs; lower blades 4-16 cm long,
3-9 mm wide, stiffly ascending to erect, glabrous or sparsely pilose to pubescent,
with prominent raised veins, flat or longitudinally wrinkled, blades of the
flag leaves often greatly reduced, often involute. Primary panicles 2-10
cm long, 0.5-7 cm wide, open or contracted, well-exserted. Spikelets
1.7-3.6 mm long, 1.2-1.8 mm wide, obovoid to ellipsoid, biconvex in side view,
glabrous or pubescent, bases narrow to attenuate, apices blunt or pointed to
beaked. Lower glumes thin, weakly veined, about 1/3 as long as the spikelets,
attached to 0.5 mm below upper glumes, clasping at the base, broadly triangular
to rounded; upper glumes with 5-9 prominent veins; lower florets
sterile; upper florets apiculate. 2n = 18.
Dichanthelium aciculare grows in sandy, open areas in the southeastern
United States, the West Indies and the Caribbean, southern Mexico, Central America,
and northern South America. It has not been reported from northernMexico. The
primary panicles are open-pollinated (sometimes briefly) and develop from April
to June; the secondary panicles are cleistogamous and develop from May into
The subspecies are often distinct when growing together, perhaps
maintained by the predominant autogamy, but they are more difficult to separate
over wider geographic areas. Rare, partly fertile putative hybrids with Dichanthelium
consanguineum, D. acuminatum,
D. ovale, D.
portoricense, and (possibly) D.
dichotomum apparently lead to some intergradation with these species.