Peruvian Muhly

Muhlenbergia pusilla Steud. Syn. Gram. 177
Muhlenbergia Bourgaei Fourn.; Hemsl. Biol. Centr. Am. Bot. 3: 539, name c Gram. 86. 1886. (Type from Valley of Mexico, Bourgean 1155, l.WK)
Annual; culms slender, erect, glabrous, cespitose, .3-30 cm. tall, much branched from near the base, the liranches erect, or the outer sometimes spreading because of the large size of the tuft; sheaths glabrous, longer than the internodes, rather prominently ncrvefl, (he lower much overlapping, Ihin, loose and flattened out, the margin hyaline; ligule thin, acutish, about 3 mm. long; blades flat or usually loosely involute, erect, glabrous beneath, minutely pubescent on the upper surface, mostly less than 5 cm. long, 1 mm. wide or less; panicles numerous, terminating the culms and the short basal often included branches, oval or oblong, narrow or rather loose, 1-4 cm. long, the branches appressed or ascending, mostly floriferous from near base, fewflowered, one or two of the lowermost naked at base, the branchlets and short pedicels appressed; glumes thin, unequal, the first narrow, acute, 1-nerved, about 1.5 mm. long, the second broad, 3-nerved, 3-toothed, about 2 mm. long, minutely scabrous on the nerves; lemma terete, lanceolate-acuminate, densely appressed-pilose on the lower half, scaberulous above, minutely bifid at apex, about 2 mm. long above the densely short-pilose callus, the awn very slender, scabrous, flexuous, 5-10 mm. long.
Type locality: Toluca, Mexico (Berlandier 1I4I).
Distribution: Dry open ground, prairies, and open pine woods, 2000-3000 meters. San Luis Potosi to Jalisco.

Muhlenbergia pulcherrima Scribn.; Beal, Grasses N. Am. 2: 240. 1896.
Annual; culms erect, cespitose, 15-25 cm. tall, much branched near base, the branches erect; sheaths striate, minutely scabrous, longer than the internodes, much overlapping toward base; ligule thin, acute, 2-3 mm. long, blades flat or loosely involute, scaberulous beneath, minutely pubescent on the upper surface, mostly less than 5 cm. long, 1 mm. wide or less; panicle narrow, rather loose, 3-5 cm. long, the branches ascending; glumes unequal, the first acute or notched, 0.5-1 mm. long, the second scaberulous, acute or 2-3-toothed, about 2 mm. long; lemma terete, narrow, gradually acuminate, 3.5-4 mm. long, minutely bifid at apex, minutely pubescent on the callus and just above, pubescent on the lower half on the contiguous margins, otherwise scaberulous only, the awn slender, flexuous, 1-1.5 cm. long. Resembling M. pusitla, difi^ering in the size, shape, and pubescence of the lemma.
TvPH locality: Chihuahua iPringle 1416).
Distribution: Drv rocks or open places in pine woods. Chihuahua, P I6V7, Hilrhcnck 766.1. 772?).

Tufted annuals. Culms 3–27 cm tall, erect, glabrous. Leaf sheaths usually longer than the internodes, smooth or scabridulous; ligules 1.5–3 mm long, membranous, acute; blades 1–5 cm long, 0.6–1.5 mm wide, flat to involute, smooth or scabridulous abaxially, sometimes shortly pubescent adaxially. Panicles 2–8 cm long, 0.3–3.4 cm wide, contracted or open; primary branches 1–5 cm long, diverging up to 80° from the rachises; pedicels 0.4–5 mm long, smooth or scabrous. Spikelets 1.4 4.2 mm long, 1-flowered; glumes smooth or scabridulous; lower glumes 0.8–2.8 mm long, narrow to broadly lanceolate, 1-veined, acute, often awn-tipped; upper glumes 0.9–3 mm long, wider than the lower glumes, lanceolate, 3 (2)-veined, truncate to acute, 2- or 3-toothed; lemmas 1.4–4.2 mm long, ovate, widest near the base, purplish mottled with dark green areas, hairy on the calluses and lower 2/3 of the lemma bodies, hairs to 0.5 mm long, apices acuminate, usually bifid and awned from between the teeth, teeth to 0.5 mm long, awns 3–10 mm long, flexuous, purplish; paleas 1.3–3.8 mm, narrowly lanceolate, acuminate to subacute; anthers 0.5–1 mm long, purplish to yellowish. Caryopses 1–1.6 mm long, fusiform, brownish. 2n = 30.

Muhlenbergiaperuviana occurs in Arizona and New Mexico, U.S.A, throughout Mexico to Guatemala and then in Argentina, Bolivia, Chile, Ecuador and Peru (Peterson and Annable 1991).

Annuals, Terrestrial, not aquatic, Stems nodes swollen or brittle, Stems erect or ascending, 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, 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 and blade differentiated, Leaf blades linear, Leaf blades very narrow or filiform, less than 2 mm wide, Leaf blades mostly flat, Leaf blade margins folded, involute, or conduplicate, 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 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 with 2-10 branches, Flowers bisexual, Spikelets pedicellate, Spikelets laterally compressed, Spikelet less than 3 mm wide, Spikelets with 1 fertile floret, 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 glabrous, Glumes present, empty bracts, Glumes 2 clearly present, Glumes equal or subequal, Glumes shorter than adjacent lemma, Glumes 1 nerved, Glumes 3 nerved, Lemmas thin, chartaceous, hyaline, cartilaginous, or membranous, Lemma similar in texture to glumes, Lemma 3 nerved, Lemma body or surface hairy, Lemma apex dentate, 2-fid, Lemma distinctly awned, more than 2-3 mm, Lemma with 1 awn, Lemma awn less than 1 cm long, Lemma awn 1-2 cm long, Lemma awn from sinus of bifid apex, Lemma awns straight or curved to base, 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 about equal to lemma, Palea 2 nerved or 2 keeled, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis, Caryopsis ellipsoid, longitudinally grooved, hilum long-linear.