Stevens' Panic Grass

Panicum stevensianum Hitchc. & Chase, Contr. U. S. Nat
Herb. 17:498. 1915.
Plants perennial, tufted, glabrous throughout; culms compressed, 30-60 cm. long, spreading, prostrate, rooting at the nodes, the flowering ends and the branches ascending; leaf -sheaths loose, much shorter than the internodes, compressed, keeled, ciliate on the overlapping margin; ligule a delicate membrane about 0.5 mm. long; blades flat, rather firm, more or less spreading, 4-10 cm. long, 5-10 mm. wide, tapering from a little above the sparsely truncate-cordate base to an acuminate apex; panicles terminal on the culm and branches, shortexserted, 6-10 cm. long, narrow, consisting of several appressed or ascending spike-like branches along an angled axis, the lower branches somewhat remote, 1.5-3 cm. long, usually longer than the internodes, the upper approximate, all spikelet-bearing to the base, the short-pediceled spikelets in crowded clusters, not secund, along a slender scabrous rachis; spikelets about 2 mm. long and 0.8 mm. wide, acute, somewhat inflated and gaping; first glume about one fourth the length of the spikelet, subacute, 3-nerved; second glume and sterile lemma equal, pointed, slightly exceeding the fruit, 3-5-nerved, the lemma inclosing a large palea and abortive perfect flower; fruit 1.9 mm. long, 0.6 mm. wide, minutely scabrous at the acute apex.
Type locality: Campo Alegre, Porto Rico.
Distribution: Porto Rico.

Perennials, Terrestrial, not aquatic, Stems trailing, spreading or prostrate, Stems nodes swollen or brittle, Stems terete, round in cross section, or polygonal, Stems branching above base or distally at nodes, Stem internodes hollow, Stems with inflorescence less than 1 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly cauline, Leaves conspicuously 2-ranked, distichous, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath smooth, glabrous, Leaf sheath hairy, hispid or prickly, Leaf sheath hairy at summit, throat, or collar, Leaf sheath and blade differentiated, Leaf blades linear, Leaf blades 2-10 mm wide, Leaf blades mostly flat, Leaf blades mostly glabrous, Leaf blades scabrous, r oughened, or wrinkled, Ligule present, Ligule a fringed, ciliate, or lobed membrane, 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 per stem or culm, Inflorescence branches more than 10 to numerous, Flowers bisexual, Spikelets pedicellate, Spikelets dorsally compressed or terete, Spikelet less than 3 mm wide, Spikelets with 1 fertile floret, Spikelets with 2 florets, Spikelet with 1 fertile floret and 1-2 sterile florets, Spikelets paired 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 5-7 nerved, Lemma glabrous, Lemma apex acute or acuminate, Lemma awnless, Lemma margins inrolled, 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, Caryopsis ellipsoid, longitudinally grooved, hilum long-linear.