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Inflorescences
Dissections:
Tripsacum dactyloides
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TRIPSACUM L. Gamagrass
Plants monoecious, rhizomatous, perennial. Culms erect or ascending; internodes glabrous, terete; nodes
glabrous. Leaves mainly basal, not distinctly distichous; sheaths terete, margins open; auricles absent; ligules
membranous or a ciliate membrane; blades flat or folded, linear (broad) to attenuate, lax, apex acuminate.
Panicles (or a spicate raceme) of 1-5 racemose branches, open, terminal, sheaths subtending the
inflorescences not inflated and spathe-like; primary branches usually unbranched with pistillate spikelets
proximal and staminate spikelets distal, branches digitate or subdigitate, spreading, not aromatic; branches
glabrous; pedicels not with a longitudinal groove, glabrous, semi-terete. Spikelets solitary (pistillate)
or paired (staminate). Staminate spikelets (2) per node, dissimilar in size, disarticulation
below the glumes, dorsiventrally compressed; both sessile or 1-sessile and 1-pedicellate; glumes 2,
membranous; florets 2, membranous, both staminate, awnless, staminate portion of the inflorescence
disarticulating as a whole. Stamens 3; anther dark reddish brown. Pistillate spikelets usually
solitary; first glumes 0-keeled, abaxial surface convex, smooth, hard and bony, glabrous, awnless;
second glumes shorter than first glumes; lower florets sterile, hyaline, entire, awnless; paleas absent or
present; upper floret pistillate, lemmas hyaline, apex entire, awnless; paleas present, hyaline.
Caryopses large. Base chromosome number x=9.
A genus of about 12 species, many of which are highly valued as cattle forage. These species are native to
North and South America. The species are either shade species or grassland species. The taxa can become an
ecological dominant in damp places.
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