Heller's Rosette Grass

Panicum helleri Nash, Bull. Torrey Club 26: 572. 1899
Panicum pernervosum Nash, Bull. Torrey Club 26: 576. 1899.
Vernal phase in clumps of few to several culms, light-green, usually somewhat bluish; culms 25-60 cm. high, slender, ascending or spreading, the lower internodes appressed-pilose, the upper often glabrous; leaf-sheaths sparsely papillose-hispid to glabrous, the papillae often without hairs as in P. Scribnerianum, ciliate on the margin; ligule about 1 mm. long; blades ascending or spreading, measuring about the same as those of P. Scribnerianum, but broadest about the middle, rather thin, glabrous on both surfaces or pubescent beneath, ciliate toward the base; panicles finally rather long-exserted, 6-12 cm. long, about three fourths as wide, more open and loosely flowered than in P. Scribnerianum; spikelets 2.9-3 mm. long, 1.6-1.7 mm. wide, obovate, turgid, blunt, glabrous, or with few scattered hairs; first glume about one third the length of the spikelet, acute; second glume and sterile lemma subequal, slightly exposing the fruit at maturity, strongly nerved; fruit 2.4-2.5 mm. long, 1.5-1.6 mm. wide; oval, obscurely apiculate.
Autumnal phase branching at all but the lowest nodes, forming loose sprawling tufts, the branches somewhat divaricate, with sheaths more commonly pubescent than those of the primary culm, the blades widely spreading, not much reduced, the long-pediceled spikelets rather conspicuous among the foliage.
Type locality; Kerrville, Texas.
Distribution: Missouri to Louisiana and New Mexico.

Panicum scribnerianum Nash, Bull. Torrey Club 22: 421. 1895
Panicum macrocarpon Torr. Fl. U. S. 143. 1823. Not P. macrocarpon LeConte, 1819.
Vernal phase in clumps of few to many culms, 20-50 cm. high, erect or ascending, often geniculate at base, glabrous or harshly puberulent or sometimes ascending papillose-pilose; leaf-sheaths rather loose, conspicuously striate, ciliate on the margin, ascending-pubescent between the nerves and papillose-hispid with spreading or ascending hairs to nearly glabrous, the papillae often without hairs; ligule about 1 mm. long; blades ascending or erect, 5-10 cm. long, 6-12 mm. wide, usually firm, acuminate, rounded and ciliate at base, glabrous on the upper surface, appressed-pubescent to glabrous beneath; panicles short-exserted, 4-8 cm. long, rarely longer, two thirds to three fourths as wide, the flexuous branches ascending ; spikelets 3 .23.3 mm. long, 2 mm. wide, obovate, turgid, blunt, sparsely pubescent to nearly glabrous; first glume about one third the length of the spikelet, acute ; second glume and sterile lemma subequal, barely or scarcely equaling the fruit at maturity, strongly nerved; fruit 2.8-2.9 mm. long, 1.8-1.9 mm. wide, broadly elliptic, minutely apiculate.
Autumnal phase branching from the middle and upper nodes at about the maturity of the primary panicle; the branches longer than the internodes, and late in the season producing crowded branchlets with ascending, not greatly reduced, blades and small, partially included, panicles from their upper nodes.
Type locality: Pennsylvania.
Distribution: Maine to British Columbia, and south to Maryland and Arizona.

Perennials, Terrestrial, not aquatic, Rhizomes present, Stems nodes swollen or brittle, Stems erect or ascending, Stems caespitose, tufted, or clustered, Stems terete, round in cross section, or polygonal, Stem internodes hollow, Stems with inflorescence less than 1 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly basal, below middle of stem, Leaves conspicuously 2-ranked, distichous, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath hairy, hispid or prickly, Leaf sheath hairy at summit, throat, or collar, Leaf sheath and blade differentiated, Leaf blades lanceolate, Leaf blades 2-10 mm wide, Leaf blades 1-2 cm wide, Leaf blades mostly flat, Leaf blades mostly glabrous, Leaf blades more or less hairy, Inflorescence terminal, Inflorescence an open panicle, openly paniculate, branches spreading, Inflorescence a contracted panicle, narrowly paniculate, branches appressed or ascending, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster p er stem or culm, Inflorescence branches more than 10 to numerous, Flowers bisexual, Spikelets pedicellate, Spikelets dorsally compressed or terete, Inflorescence or spikelets partially hidden in leaf sheaths, subtended by spatheole, Spikelet less than 3 mm wide, Spikelets with 1 fertile floret, Spikelets with 2 florets, Spikelets solitary at rachis nodes, Spikelets all alike and fertille, Spikelets bisexual, Spikelets disarticulating below the glumes, Rachilla or pedicel glabrous, Glumes present, empty bracts, Glumes 2 clearly present, Glumes distinctly unequal, Glumes equal to or longer than adjacent lemma, Glume equal to or longer than spikelet, Glumes 3 nerved, Glumes 4-7 nerved, Lemma similar in texture to glumes, Lemma coriaceous, firmer or thicker in texture than the glumes, Lemma becoming indurate, enclosing palea and caryopsis, Lemma 3 nerved, Lemma 5-7 nerved, Lemma 8-15 nerved, Lemma glabrous, Lemma apex truncate, rounded, or obtuse, Lemma awnless, Lemma margins in rolled, tightly covering palea and caryopsis, Lemma straight, Palea present, well developed, Palea about equal to lemma, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis.

Dichanthelium oligosanthes, known as Heller's rosette grass, fewanther obscuregrass, and few-flowered panicgrass, is a frost-tolerant, perennial grass species native to North America. It is found primarily in the contiguous United States with specimens also reported in British Columbia and Alberta in Canada, as well as south of the Rio Grande in northern Mexico. D. oligosanthes is most frequently in partially shaded glens within woods, recently cut forests, and grassy banks.

The species is primarily cleistogamous, with individual florets often self pollinate without opening. Despite being a member of the grass subfamily Panicoideae which includes many species which utilize C4 photosynthesis, D. oligosanthes retains the more ancestral trait, using a C3 photosynthetic pathway.

The genome of Dichanthelium oligosanthes is carried on nine chromosomes and is estimated to be between 750 and 950 megabases in size. A draft genome assembly was generated from the progeny of a single self-pollinated plant collected from the Shaw Nature Reserve near Gray Summit, Missouri.