Amazon Viper Grass

Leptochloa panicoides (Presl) Hitchc. Am. Jour. Bot 21:137. 1934.
Megastachya panicoides Presl, Rel. Haenk. 1: 283. 1830.
Poa panicoides Kunth, R6v. Gram. Suppl. XXVIII. 1830. (Based on Megastachya panicoides
Presl.) Eragrostis panicoides (Presl) Steud. Syn. Gram. 278. 1854. (Based on Megastachya panicoides
Presl.) Leptochloa floribunda Doll, in Mart. Fl. Bras. 2': 89. 1878. (Type from along the Amazon River
between Manaos and Santarem, Spruce.) Diplachne Halei Nash, Bull. N. Y. Bot. Gard. 1: 292. 1899. (Type from Louisiana, Hale.) Leplochloa Halei Scribn. & Merr. Bull. U. S. Dep. Agr. Agrost. 24: 27. 1901. (Based on Diplachne
Halei Nash.)
Annual; culms erect, branching, glabrous, 40 cm. to more than a meter tafl; sheaths glabrous or scabrous, mostly longer than the internodes; ligule membranaceous, truncate, erose, 1-2 mm. long; blades flat, acuminate, 10-25 cm. long, 3-10 mm. wide, scabrous, especially on the margins; terminal inflorescence 12-30 cm. long, mostly 4-8 cm. wide, the numerous spreading spikes rather crowded, the lowermost as much as 8 cm. long (usually about 4 cm.); spikelets scarcely crowded, pedicellate, 5-7-flowered, about 4 mm. long; glumes acute or acuminate, the first narrow, 1-nerved, 1 mm. long, the second much broader, 1-3-nerved, 2 mm. long; lemmas 2.5-3 mm. long, densely pubescent on the margins near the base, the tip minutely lobed, mucronate.
Type locality: Acapulco, Mexico (Haenke).
Distribution: Mud flats and lake shores, Indiana to Missouri, and southward to Mississippi and Texas; Sinaloa, Guerrero, and Tepic; also in Brazil.

Annuals, Terrestrial, not aquatic, Stems nodes swollen or brittle, Stems erect or ascending, Stems geniculate, decumbent, or lax, sometimes rooting at nodes, Stems caespitose, tufted, or clustered, Stems terete, round in cross sect ion, or polygonal, Stems compressed, flattened, or sulcate, 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 at summit, throat, or collar, Leaf sheath and blade differentiated, Leaf blades linear, Leaf blades 2-10 mm wide, Leaf blades 1-2 cm wide, Leaf blades mostly flat, Leaf blade margins folded, involute, or conduplicate, Leaf blades mostly glabrous, Leaf blades scabrous, roughened, or wrinkled, Ligule present, Ligule an unfringed eciliate membrane, Inflorescence terminal, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Inflorescence a panicle with narrowly racemose or spicate branches, Inflorescence branches more than 10 to numerous, Infl orescence branches 1-sided, Flowers bisexual, Spikelets sessile or subsessile, Spikelets laterally compressed, Spikelet less than 3 mm wide, Spikelets with 2 florets, Spikelets with 3-7 florets, Spikelets solitary at rachis nodes, Spikelets all alike and fertille, Spikelets bisexual, Spikelets disarticulating above the glumes, glumes persistent, Spikelets disarticulating beneath or between the florets, Spikelets secund, in rows on one side of rachis, Rachilla or pedicel glabrous, Glumes present, empty bracts, Glumes 2 clearly present, Glumes distinctly unequal, Glumes shorter than adjacent lemma, Glumes keeled or winged, Glumes 1 nerved, Lemmas thin, chartaceous, hyaline, cartilaginous, or membranous, Lemma 3 nerved, Lemma body or surface hairy, Lemma apex dentate, 2-fid, Lemma awnless, Lemma mucronate, very shortly beaked or awned, less than 1-2 mm, Lemma straight, Palea present, well developed, Palea membranous, hyaline, Palea about equal to lemma, Palea 2 nerved or 2 keel ed, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis.