Jepson Flora Project: Jepson Interchange    

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Jepson Interchange (more information)
©Copyright 1993 by the Regents of the University of California

  • Up-to-date information about California vascular plants is available from the Jepson eFlora.



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.



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.


P. wheeleri Vasey

Perennial from short rhizomes, ± tufted, generally 3.5–8 dm, dioecious
Leaf: sheaths open 1/3–2/3 length, lower often finely reflexed-scabrous or short-hairy; lower ligules 0.5–2 mm, truncate to rounded, scabrous; blade 1.5–3.5 mm wide, soft to ± firm, flat or folded; sterile stem blades folded and ± inrolled, upper surface generally ± finely hairy
Inflorescence generally 5–12 cm, ovate, sparse; branches generally 1–4, ± ascending to spreading, ± scabrous
Spikelet: callus glabrous; lemma 3–6 mm, glabrous to sparsely hairy on keel and marginal veins, generally sparsely scabrous
Flower pistillate (anthers ± vestigial)
Chromosomes: 2n=56,63,70–91
Ecology: Common (especially SN). Mtns, open forest in rich soil
Elevation: 1300–3800 m.
Bioregional distribution: Klamath Ranges, High North Coast Ranges, High Cascade Range, High Sierra Nevada, Great Basin Floristic Province
Distribution outside California: to s Canada, Colorado
Flowering time: Summer
Formerly mistaken for P. nervosa (Hook.) Vasey
Horticultural information: DRY: 1, 2, 3; REVEG.

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