Trisetum cernuum Trin.

Chile Central

Trisetum cernuum Trin. Mem. Acad. vSt.-Petersb. VI 1:61. 1830.
Avena nulkaensis Presl, Rel. Haenk. 1: 254. 1830. (Type from Nootka Sound, Vancouver Island,
Haenke.) Avena cernua Kunth, R4v. Gram. Suppl. XXVI. 1830. (Based on Trisetum cernuum Trin.) Tnselum Sandhergit Beal, Grasses N. Am. 2: 378. 1896. (Tvpe from Mount Stuart, Washington,
Sandberg if Leiberg 823.) Triselum nutkaense Scribn. & Merr.; Davy. Univ. Calif. Publ. Bot. 1: 63. 1902. (Based on Avena
nulkaensis Presl.) Trisehim cernuum var. luxurians Louis-Marie, Rhodora 30: 213. 1928. (Type from Seaside,
Oregon, Shear &■ Scribner 1705.) Trisehim cernuum var. luxurians f. pubescens Louis-Marie, Rhodora 30: 213. 1928. (Type from
Eureka, California.) Triseltim cernuum var. Sandbergii Louis-Marie, Rhodora 30: 214. 1928. (Based on T. Sandbergii
Beal.) Trisetum cernuum f. pubescens G. N. Jones. Univ. Wash. Publ. Biol. 5: 108. 1936. (Based on T.
cernuum var. luxurians f. pubescens Louis-Marie.)
Perennial; culms rather lax, glabrous, often scaberulous below the panicle, 60-120 cm. tall; sheaths glabrous, scabrous, or sparsely pilose; ligule truncate, erose-dentate, 2-4 mm. long; blades thin, flat, lax, scabrous, 6-12 mm. wide; panicle open, lax, drooping, 15-30 mm. long, the axis more or less scabrous, the branches verticillate, filiform, flexuous, scabrous, spreading or drooping, spikelet -bearing toward the ends; spikelets 6-12 mm. long, with usually 3 distant florets, the first longer than the second glume, the slender curved rachilla-joints nearly 2 mm. long, Wllous, the hairs of the callus 0.5-1 mm. long; first glume narrow, acuminate, 1-nerved, 0.5-2 mm, long, the second broad, 3-nerved, 3-4 mm. long, occasionally reduced; lemmas glabrous or slightly scaberulous, 5-6 mm. long, the teeth setaceous; awn slender, curved, flexuous or loosely spiral, mostly 5-10 mm. long, attached 1-2 mm. below the tip.
Type locality: Sitka, Alaska.
Distribution: Moist woods. Alberta to southeastern Alaska, and southward to western Montana and northern California.

Perennials, 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 section, or polygonal, Stem internodes hollow, Stems with inflorescence less than 1 m tall, Stems with inflorescence 1-2 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly basal, below middle of stem, 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 and blade differentiated, Leaf blades linear, Leaf blades 2-10 mm wide, Leaf blades 1-2 cm wide, Leaf blades mostly flat, Leaf blades mostly glabrous, Leaf blades scabrous, roughened, or wrinkled, Ligule present, Ligule an unfringed eciliate membrane, Inflorescence terminal, Inflorescence an open panicl e, openly paniculate, branches spreading, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Inflorescence lax, widely spreading, branches drooping, pendulous, Inflorescence branches more than 10 to numerous, Lower panicle branches whorled, Flowers bisexual, Spikelets pedicellate, Spikelets sessile or subsessile, Spikelets laterally compressed, Spikelet less than 3 mm wide, 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, Rachilla or pedicel hairy, Glumes present, empty bracts, Glumes 2 clearly present, Glumes equal or subequal, Glumes equal to or longer than adjacent lemma, Glumes keeled or winged, Glumes 1 nerved, Glumes 3 nerved, Lemma similar in texture to glumes, Lemma 5-7 nerved, Lemma glabrous, Lemma apex dentate, 2-fid, Lemma distinctly a wned, more than 2-3 mm, Lemma with 1 awn, Lemma awn 1-2 cm long, Lemma awn from sinus of bifid apex, Lemma awn subapical or dorsal, Lemma awn once geniculate, bent once, Lemma margins thin, lying flat, Lemma straight, Callus or base of lemma evidently hairy, Callus hairs shorter than lemma, Palea present, well developed, Palea membranous, hyaline, Palea longer than lemma, Palea 2 nerved or 2 keeled, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis.

Trisetum cernuum là một loài thực vật có hoa trong họ Hòa thảo. Loài này được Trin. miêu tả khoa học đầu tiên năm 1830.