| TREATMENT FROM THE JEPSON MANUAL (1993) |
previous taxon |
next taxon
Jepson Interchange (more information) |
|
|
©Copyright 1993 by the Regents of the University of California
For up-to-date information about California vascular plants, visit the Jepson eFlora. |
AND IS MAINTAINED FOR ARCHIVAL PURPOSES ONLY |
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]
| Introduced |
Dioecious
Stem < 2 m, glaucous or gray-green
Leaves: submersed leaves 1.5–3.5 cm; midrib ± flat, wider than divisions, divisions < 7 mm, 20–30 per leaf
Inflorescence axillary, ± emergent
Staminate flower: stamens 8; ovary vestigial
Pistillate flower: stamens 0
Fruit generally 0 in CA
Ecology: Common. Ponds, ditches, streams, lakes
Elevation: < 500 m.
Bioregional distribution: North Coast, Cascade Range Foothills, Central Western California, South Coast
Distribution outside California: warm temperate, tropical worldwide; native to S.America
Cult and naturalized plants generally pistillate, clonal
Synonyms: M. brasiliense Cambess