Plants annual; tufted. Culms 2-30 cm, bases often prostrate or decumbent, strongly branching. Sheaths glabrous or sparsely hirsute; ligules 0.7-1.5 mm, lacerate; blades 1-7 cm long, 1-2 mm wide, glabrous or puberulent. Panicles 2-6 cm. Lateral spikelets 1.5-2.3 mm, on 1-1.3 mm pedicels; central spikelets 2.5-3.2 mm, on 0.3-0.6 mm pedicels. Glumes 1.3-1.8 mm, flabellate, lobes rounded, awns 0.1-0.6 mm; lemmas 2.5-3.2 mm, central awns 3-8 mm, lateral awns to 1 mm; anthers 0.5-0.8 mm. 2n = 20, 60.

Aegopogon tenellus usually grows between 1550-2150 m in shady habitats of moist canyons, but it is sometimes found along roadsides and in other open areas. Its range extends from southern Arizona into northern South America. Plants in which the lateral spikelets are reduced have been called Aegopogon tenellus var. abortivus (E. Fourn.) Beetle, but such spikelets (and central spikelets with reduced awns) are also found in plants with normal spikelets, so taxonomic recognition is not warranted.

Annuals, Terrestrial, not aquatic, Stems trailing, spreading or prostrate, Stems nodes swollen or brittle, Stems geniculate, decumbent, or lax, sometimes rooting at nodes, Stems caespitose, tufted, or clustered, 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, Leaf tips flexuous, drooping, blades thin, lax, soft, 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, Leaves borne on branches, Leaf blades linear, Leaf blades very narrow or filiform, less than 2 mm wide, Leaf blades mostly flat, Leaf blades mostly glabrous, Leaf blades more or less hairy, Ligule present, Ligule an unfringed eciliate membrane, Inflorescence terminal, Inflorescence a dense slender spike-like panicle or raceme, branches contracted, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Inflorescence a panicle with narrowly racemose or spicate branches, Inflorescence single raceme, fascicle or spike, Inflorescence branches 1-sided, Flowers bisexual, Spikelets sessile or subsessile, Spikelets laterally compressed, Spikelet less than 3 mm wide, Spikelets with 1 fertile floret, Spikelets 3 per node, Spikelets bisexual, Inflorescence disarticulating between nodes or joints of rachis, rachis fragmenting, Spikelets falling with parts of disarticulating rachis or pedicel, Spikelets secund, in rows on one side of rachis, Rachilla or pedicel g labrous, Glumes present, empty bracts, Glumes 2 clearly present, Glumes equal or subequal, Glumes shorter than adjacent lemma, Glumes 1 nerved, Lemmas thin, chartaceous, hyaline, cartilaginous, or membranous, Lemma similar in texture to glumes, Lemma 3 nerved, Lemma glabrous, Lemma apex dentate, 3-5 fid, Lemma distinctly awned, more than 2-3 mm, Lemma with 1 awn, Lemma with 3 awns, Lemma awn less than 1 cm long, Lemma awn 1-2 cm long, Lemma awned from tip, Lemma awns straight or curved to base, Lemma margins thin, lying flat, Lemma straight, Palea present, well developed, Palea membranous, hyaline, Palea about equal to lemma, Palea 2 nerved or 2 keeled, Palea keels winged, scabrous, or ciliate, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis, Ca

Common Name: fragilegrass

Duration: Annual

Nativity: Native

Lifeform: Graminoid

General: Delicate, tufted annual with weak stems 2-30 cm, bases often prostrate or decumbent, strongly branching.

Vegetative: Sheaths glabrous or sparsely hirsute; blades 1-7 cm long, 1-2 mm wide, thin, flat; ligules 0.5-1.5 mm, lacerate.

Inflorescence: Raceme 2-6 cm on filiform, slightly zig-zag axis, bearing minute basal stumps of peduncles after spikelets fall; spikelets 1.5-2.3 mm, on 1-1.5 mm pedicels; kinked peduncle is slender and fragile, bearing three spikelets on large flattened pedicels; glumes 1-2 mm, fan-shaped, lobes rounded, awns about 0.5 mm; lemmas 2.5-3 mm, central awns 3-8 mm, lateral awns to 1 mm.

Ecology: Found in partial shade, often of trees or boulders, in shady moist canyons and rarely along roads from 5,000-7,000 ft (1524-2134 m); flowers August-October.

Notes: The minute size along with the fan shaped glumes and the slight reddish tinge help to identify this species. This taxa is undergoing revision. Peterson in 2009 put this species in Muhlenbergia cenchroides, but it alternately has also been noted as Muhlenbergia geminiflora by Peterson and as M. uniseta by Columbus. Tropicos suggests this species is M. cenchroides.

Ethnobotany: Unknown

Etymology: Aegopogon is from Greek aix, or aigos, for a goat and pogon, a beard, while tenellus is from Latin for delicate or dainty.

Synonyms: Aegopogon tenellus, Aegopogon tenellus var. abortivus, Lamarckia tenella

Editor: SBuckley, 2010