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.



Elizabeth McClintock

Annual, perennial herb, shrub, generally monoecious, generally aquatic
Leaves cauline, opposite, alternate, or whorled; submersed blades with pinnate, thread-like divisions; aerial leaves simple, entire to divided
Inflorescence: panicle, raceme, or spike; flowers 1 or clustered, short-pedicelled to ± sessile
Flower generally unisexual (bisexual in Haloragis ), small, biradial; calyx tube short, fused to ovary, lobes 2–4; petals generally 2–4; stamens 4 or 8, filaments generally short; ovary inferior, chambers 1–4, styles 2–4, separate, stigmas generally plumose
Fruit fleshy or nut-like, dehiscent or not
Seeds generally 1 per chamber
Genera in family: 6–8 genera, ± 100 species: especially s hemisphere, some cultivated.



Perennial from rhizomes, sometimes with overwintering bulblets, generally monoecious
Stems simple or branched, generally open, generally green
Leaves: submersed leaves whorled, 3–6 per node, pinnate divisions thread-like; emergent leaves opposite, leaf- or bract-like, entire to pinnately divided
Inflorescence spike-like, terminal, or flowers clustered, axillary, generally emergent
Flower unisexual; lower pistillate; middle sometimes bisexual; upper staminate; calyx lobes 4; petals generally 4, ephemeral on staminate flowers, minute or 0 on pistillate flowers; stamens generally 8; ovary 4-chambered, stigma plumose
Fruit: segments 4, nut-like
Seed 1 per chamber
Species in genus: ± 40 species: worldwide
Etymology: (Greek: many leaves, from leaf divisions)
Reference: [Aiken & McNeill 1980 J Linn Soc Bot 80:213–222]


M. verticillatum L.

Monoecious; bulblets sometimes present
Stem > 2.5 m
Leaves: submersed leaves < 2.5 cm; midrib and divisions linear; divisions < 10 mm, 18–34 per leaf
Inflorescence: spike, 5–12 cm, emergent; leaves 3–8(10) mm, lower >> flowers, upper 2–3 X > flowers
Ecology: Lakes, marshes
Elevation: < 1500 m.
Bioregional distribution: Klamath Ranges, n High Sierra Nevada, Modoc Plateau
Distribution outside California: to British Columbia, eastern US, Eurasia
Horticultural information: TRY.

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