TREATMENT FROM THE JEPSON MANUAL	previous taxon | next taxon Jepson Interchange (more information)
	©Copyright 1993 by the Regents of the University of California Print edition is available from the University of California Press

	The second edition of The Jepson Manual (2012) is available from the University of California Press
	See also the Jepson eFlora, which parallels the Second Edition

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). [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.

POA

BLUEGRASS

Robert J. Soreng

Annual, perennial herb, some ± dioecious
Stem 0.3–12 dm
Leaf: sheath open to closed (best observed on upper stem leaf); ligule thin, flexible; blade grooved above on both sides of midvein, flat, folded, or inrolled, generally smooth or scabrous on veins, generally prow-tipped
Inflorescence panicle-like; branches appressed to drooping
Spikelet generally compressed, breaking between florets; glumes 2, similar, generally < lowest lemma, awnless; florets generally 2–6; callus indistinct, often with obvious tuft of long cobwebby hairs; lemma generally keeled to base, of same texture as glumes, awnless, veins generally 5, ± converging near tip; palea well developed, keels generally scabrous; fertile anthers 0.2–4.5 mm; ovary glabrous
Species in genus: ± 500 species: temp and cool regions
Etymology: (Greek: ancient name)
Reference: [Soreng 1991 Syst Bot 16:507–528]
CA is center of diversity in North America. Spikelet features best observed on lowest florets of spikelet.

Native

P. secunda J. Presl

Perennial, densely cespitose, 1.5–10 dm
Leaf: sheath open 3/4 length to near base; ligule 0.5–10 mm, truncate to acuminate, sometimes scabrous; blade generally 0.5–3 mm wide, soft to firm, flat to folded or inrolled
Inflorescence 2–25 cm, often ± 1-sided, generally linear to lanceolate, generally dense; branches generally appressed to ascending (generally spreading only in flower), ± scabrous
Spikelet ± cylindric or little compressed; upper internodes generally > 1.2 mm; callus glabrous or with a ring of short hairs; lemma 3.5–5 mm, weakly keeled to rounded across lower back, glabrous to ± evenly short-hairy across body (rarely soft-hairy only on veins), smooth to scabrous
Flower: anther 1.5–3 mm
Chromosomes: 2n=42–106 (mostly high polyploids)
Ecology: Common. Many habitats
Elevation: 0–3800 m.
Bioregional distribution: California
Distribution outside California: to Alaska, Rocky Mtns, nw Mexico, also in S.America
Many ecological forms; subspp. tend to intergrade.

Native

subsp. secunda

ONE-SIDED BLUEGRASS

Plant 1.5–10 dm
Leaf: ligule 2–10 mm, acute to acuminate, smooth or sparsely scabrous; blade 0.5–3 mm wide, soft, generally flat, soon withering, sometimes glaucous, basal often thread-like
Inflorescence generally 2–15 cm
Spikelet: lemma 4–5 mm, base ± evenly short-hairy (sometimes nearly glabrous); palea keels and between them generally hairy in lower 1/2
Chromosomes: 2n=±84 most often
Ecology: Common. Habitat and range of sp
Elevation:
Bioregional distribution: California
Flowering time: Spring–early summer (mid-summer in subalpine)
Synonyms: P. canbyi (Scribner) Howell, P. gracillima Vasey, P. incurva Scribner & Williams, P. sandbergii Vasey, P. scabrella (Thurb.) Vasey
Many ecological forms have been named, all intergrade completely, probably do not warrant taxonomic recognition
Horticultural information: DRY: 1, 2, 3, 4, 5, 6, 7, 8, 9, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24; some forms tolerate IRR.