POACEAE

GRASS FAMILY

James P. Smith, Jr., except as specified

Annual to bamboo-like; roots generally fibrous
Stem generally round, hollow; nodes swollen, solid
Leaves alternate, 2-ranked, generally linear; sheath generally open; ligule membranous or hairy, at blade base
Inflorescence various (of generally many spikelets)
Spikelet: glumes generally 2; florets (lemma, palea, flower) 1–many; lemma generally membranous, sometimes glume-like; palea generally ± transparent, ± enclosed by lemma
Flower generally bisexual, minute; stamens generally 3; stigmas generally 2, generally plumose
Fruit: achene-like grain
Genera in family: 650–900 genera; ± 10,000 species: worldwide; greatest economic importance of any family (wheat, rice, maize, millet, sorghum, sugar cane, forage crops, ornamental, weeds; thatching, weaving, building materials)
Reference: [Hitchcock 1951 Manual grasses US, USDA Misc Publ 200; Clayton & Renvoise 1986 Kew Bull Add Series 13]
See Glossary p. 26 for illustrations of general family characteristics. Generally wind-pollinated.

MUHLENBERGIA

MUHLY

Paul M. Peterson

Annual, perennial herb, sometimes mat-like, often rhizomed
Stem decumbent to erect, ± clumped
Leaves basal and cauline; sheath open; ligule membranous, entire to irregularly toothed, sometimes with 1 large tooth on each side; blade flat to rolled
Inflorescence panicle-like, narrow to open; branches spreading to appressed
Spikelet: glumes subequal, generally 1-veined, short-pointed to awned, upper glume sometimes 3-veined; florets 1, sometimes 2, breaking above glumes; lemma short-pointed to awned, glabrous to hairy, 3-veined; palea < to = lemma
Fruit ± fusiform, reddish brown, generally falling with lemma and palea
Species in genus: ± 160 species: temp Am, s Asia
Etymology: (H.L.E. Muhlenberg, Pennsylvania botanist, 1753–1815)
Reference: [Reeder 1981 in Gould and Moran 1981 San Diego Soc Nat Hist Memoir 12:67–78]
Horticultural information: STBL.

Native

M. arsenei Hitchc.

TOUGH MUHLY

Perennial; rhizomes ± short
Stem 1.5–4 dm, decumbent at base
Leaf: ligule 1–2 mm, acuminate, toothed, ± decurrent to sheath, with 1 large tooth on each side; blade 1–5 cm, < 2 mm wide, rolled
Inflorescence 4–12 cm, < 3 cm wide, narrow; branches ascending to appressed, loosely flowered
Spikelet: glumes 2–3 mm, acute, ± short-awned, awn < 1 mm; lemma 3.5–5 mm, short-soft-hairy on lower half, awn 4–12 mm; palea short-soft-hairy on lower half; anther 1.6–3 mm, purple
Ecology: Limestone rock outcrops, slopes
Elevation: 1400–1860 m.
Bioregional distribution: Desert Mountains (Clark Mtns)
Distribution outside California: to se Utah, n New Mexico, n Baja California
Flowering time: Aug–Sep