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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.



Raymond Cranfill, except as specified

Annual or perennial herb, often rhizomed, often of wet open places, generally monoecious; roots fibrous, hairy
Stem generally 3-sided
Leaves often 3-ranked; sheath generally closed; ligule generally 0; blade (0) various, parallel-veined
Inflorescence: spikelets variously clustered; flowers generally sessile in axil of flower bract
Flower small, generally wind-pollinated; perianth 0 or bristle-like; stamens generally 3, anthers attached at base, 4-chambered; ovary superior, 1-chambered, 1-ovuled, style 2–3-branched
Fruit: achene, generally 3-sided
Genera in family: ± 110 genera, 3600 species: worldwide, especially temp
Reference: [Tucker 1987 J Arnold Arbor 68:361–445]
Difficult: taxa differ in technical characters of inflorescence and fruit.



Joy Mastrogiuseppe

Perennial, cespitose or from rhizomes, generally monoecious
Stem generally sharply 3-angled, generally solid
Leaves 3-ranked, generally glabrous except generally scabrous on midrib, margin; sheath closed, back (blade side of stem) green, ribbed, front generally thin, translucent, forming generally U-shaped mouth at top
Inflorescence: spikelets generally several–many, arrayed in raceme, panicle, or head-like cluster, each 1–many-flowered, generally subtended by a spikelet bract
Flowers unisexual, each subtended by 1 flower bract; perianth 0
Staminate flower: stamens generally 3
Pistillate flower enclosed by perigynium (sac-like bract); perigynium body 2–3-sided or round, wall generally delicate; perigynium beak tip open, often notched; style 1, generally deciduous, stigmas 2–4, exserted
Fruit 2–4-sided
Etymology: (Latin: cutter, from sharp leaf and stem edges)
Reference: [Standley 1985 Syst Bot Monogr 7:1–106]
Fully mature perigynia needed for identification, so are described under "FR" (long-persistent perigynia are often atypical); perigynium "front" faces spikelet axis; "fruit" refers to achene body (excluding beak). "Shredding" lower leaf sheath fronts become a network or fringe of veins; some others shred longitudinally only. Difficult because of many species and minute key characters; longer key statements and descriptions are designed to enhance both ease and probability of correct identification. Group descriptions are assumed in specific descriptions
Horticultural information: Many species especially those with rhizomes are INVASIVE. This is one of the most effective genera for knitting moist or wet soil.


C. aquatilis Wahlenb.

(Group 6)
Inflorescence generally open; lowest spikelet bract leaf-like, > 1/2 inflorescence; pistillate flower bract tip often white
Pistillate flower: style often exserted
Fruit: perigynium faces unveined, weakly papillate, beak tip notched < 0.1 mm, glabrous; fruit 1.1–1.8 mm, 0.7–1.6 mm wide, shiny
Chromosomes: 2n=72,74,76,80
Ecology: Wet places
Elevation: < 3200 m.
Bioregional distribution: Northwestern California, High Cascade Range (Butte Co.), High Sierra Nevada, Central Coast, San Bernardino Mountains, Warner Mountains, White and Inyo Mountains
Distribution outside California: to Alaska, e Canada; Europe


var. aquatilis

Leaf: blade 3–8 mm wide; sheath front not purple-dotted, mouth white or pale brown
Inflorescence: lowest internode 2–18 cm; lateral spikelets 1–10 cm, 3–7 mm wide, stalks 0 or generally erect, < 4.2 cm, tip generally pistillate; lowest spikelet bract generally ± = inflorescence
Fruit: perigynium 2–3.6 mm, 1.2–2.3 mm wide, ± red-dotted or -blotched, beak 0.1–0.2 mm, thickened
Chromosomes: 2n=72,76,78,80
Ecology: Habitats of sp.
Bioregional distribution: Klamath Ranges, North Coast Ranges, High Sierra Nevada, San Bernardino Mountains, Warner Mountains, White and Inyo Mountains
Distribution outside California: to Alaska, e Canada; n Europe
Horticultural information: TRY; STBL.

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