Paspalum setaceum Michx.

Paspalum setaceum Michx. Fl. Bor. Am. 1 : 43. 1803
A tufted branched perennial with narrow fiat pubescent leaf-blades and glabrous or pubescent spikelets. Stems slender, 2-7 dm. tall; basal leaf-sheaths densely pubescent with long hairs, the upper ones pubescent only on the margins; blades 1.5 dm. long or less, rarely somewhat longer, usually 2.5-5 mm. wide, sometimes a little broader, linear, strict and erect or ascending, fiat, of medium texture, densely pubescent on both siurfaces with long hairs; racemes single, slender, 4-8 cm. long, sometimes a little longer, the rachis about 0.6 mm. wide; spikelets either single or in pairs, on shorter puberulent pedicels, about 1.5 mm. long and 1.3 mm. wide, broadly obovate, the first scale wanting, the second 3-nerved, glabrous or pubescent with spreading glandular-tipped hairs, the third 2-nerved, the midnerve rarely if ever present, glabrous or pubescent, the fruiting scale yellowish-white.
Type locality : Carolina.
Distribution : New Hampshire to Nebraska, and south to Florida and Texas; Cuba.

Perennials, Terrestrial, not aquat ic, Rhizomes present, Rhizome short and compact, stems close, Stems nodes swollen or brittle, Stems erect or ascending, Stems caespitose, tufted, or clustered, Stems terete, round in cross section, or polygonal, Stem internodes solid or spongy, 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 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, Leaf blades scabrous, roughened, or wrinkled, Ligule present, Ligule an unfringed eciliate membrane, Inflorescence terminal, Inflorescence solitary, with 1 spike, f ascicle, glomerule, head, or cluster per stem or culm, Inflorescence a panicle with narrowly racemose or spicate branches, Inflorescence single raceme, fascicle or spike, Inflorescence with 2-10 branches, Inflorescence spikelets arranged in a terminal bilateral spike, Inflorescence branches 1-sided, Inflorescence branches paired or digitate at a single node, Inflorescence branches paired racemes, V-shaped, Rachis dilated, flat, central axis to which spikelets are attached, Rachis angular, 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, Spikelets secund, in rows on one side of rachis, Rachilla or pedicel glabrous, Glumes present, empty bracts, Glumes 1 clearly present, the other greatly reduced or absent, Glumes distinctly unequal, Glumes equal to or longer than adjacent lemma, Glume equal to or longer than spikelet, Glumes 3 nerved, Lemma similar in texture to glumes, Lemma 3 nerved, Lemma glabrous, Lemma apex truncate, rounded, or obtuse, Lemma awnless, Lemma straight, Palea present, well developed, Palea shorter than lemma, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis, Caryopsis white.

Paspalum setaceum is a species of grass known by several common names, including thin paspalum. It is native to the Americas, where it can be found in the eastern and central United States, Ontario in Canada, Mexico, Central America, and the Caribbean. It can be found in other areas of the world as an introduced, and often invasive, species, including many Pacific Islands. It is a weed of lawns and turf.

This grass is a perennial with erect or prostrate stems that can exceed one meter in length. The flat leaf blades are hairless to slightly hairy. They vary in color. The panicle has up to 6 branches up to 17 centimeters long lined with small oval to rounded spikelets. There are several varieties of this species which can be distinguished in part by color. Some authors do not recognize varieties.

Varieties include:

Paspalum setaceum var. ciliatifolium (fringe-leaf paspalum) - dark green or purplish leaf blades. Widespread. Grows as a weed in the Pacific Islands. Paspalum setaceum var. longepedunculatum (barestem paspalum) - yellow-green leaf blades Paspalum setaceum var. muhlenbergii (hurrahgrass) - North America Paspalum setaceum var. psammophilum (sand paspalum, beadgrass, slender beadgrass, tufted beard-grass) - hairy leaf blades. East Coast of the United States. Paspalum setaceum var. setaceum (thin paspalum) - hairy gray-green leaf blades Paspalum setaceum var. stramineum (yellow sand paspalum) - yellow-green to dark green leaf blades Paspalum setaceum var. villosissimum (hairy paspalum) - gray-green leaf blades Wikimedia Commons has media related to Paspalum setaceum.

Paspalum setaceum là một loài thực vật có hoa trong họ Hòa thảo. Loài này được Michx. mô tả khoa học đầu tiên năm 1803.