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DICHANTHELIUM (A.S. Hitchc. & Chase) Gould Rosettegrass
Plants caespitose, perennial. Culms erect (vernal form) or mat forming (autuminal form), glabrous or pubescent
or hairy; internodes solid or hollow, terete. Leaves of two kinds, basal short and wide (basal
rosette present) and cauline narrow and linear or not differentiated into two kinds (basal
rosette absent), not distinctly distichous; sheaths terete; ligules a line of hairs or membrane or
ciliate membrane or absent; blades usually flat (broad or narrow). Vernal panicles
open; primary branches spreading (secondary also spreading), terminating in a spikelet; autuminal
panicles reduced and axillary (frequently with 3-7 spikelets), primary branches terminating in a
spikelet; bristles absent below spikelets. Spikelets solitary, not embedded in branch, dorsiventrally
compresssed; disarticulation below spikelets; florets 2; lower sterile and staminate or without stamens;
upper fertile, more than eight tenths lower floret length; first glumes present (much shorter than
second glume), not fused with callus, not encircling spikelet base or encircling spikelet base, awnless;
second glumes present (about spikelet length), not saccate, 3- or 7- or 9-veined; lemma of upper florets
indurate, smooth, yellow to green, margins involute, not differentiated at apex, awnless; palea of
upper florets present. Stamens 3; anthers tan or golden brown or reddish brown. Base chromosome number x=9.
Most taxa are 2n=18 with a few 2n=36.
A variable genus of 70 or more species mostly from temperate regions of the America's. Gould (1974)
reduced the number of species significantly for North America. Hansen and Wunderlin (1988) refined Goulds work
in treating Florida Dichanthelium. Some authors treat these taxa as a subgenus of Panicum. However,
Dichanthelium is a C3 genus whereas "true" Panicum is C4.
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