| TREATMENT FROM THE JEPSON MANUAL (1993) |
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©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, aquatic, freshwater or marine, bisexual, monoecious, or dioecious
Leaves basal or cauline, alternate, opposite, or whorled, generally ± sheathing at base, glabrous
Inflorescence: cyme; flowers 1–few, subtended by ± sheathing, entire or lobed bract; staminate flowers sometimes deciduous, free-floating
Flower radial; perianth tube 0 or much elongated, peduncle-like in flower; sepals (0)3, green; petals (0)3, colored or white; stamens (1)3–many, generally in 1+ series; ovary inferior, chamber 1, placentas parietal or basal, ovules 1–many; style lobes generally 3, linear, lobed or notched
Fruit: achene or berry-like and dehiscing irregularly, linear to spheric, submersed
Genera in family: ± 17 genera, ± 130 species: worldwide; some cultivated for aquaria, others noxious weeds.
Perennial, rooting at nodes, generally submersed, dioecious or some flowers bisexual
Stem slender, generally branched
Leaves opposite or whorled, generally 3 per whorl, sessile; blade margin minutely, finely toothed
Inflorescence: flowers solitary, axillary, sessile or peduncled; bract generally notched
Staminate flower floating, deciduous or not; perianth tube elongated, slender, peduncle-like; stamens 3–9
Pistillate flower floating; perianth tube elongated, slender, peduncle-like; style slender, stigmas 3, simple or 2-lobed
Fruit cylindric to ovoid
Seeds several
Species in genus: ± 12 species: temp and tropical Am
Etymology: (Greek: of marshes)
[St. John, 1965 Rhodora 67:1–35,155–180]
| Native |
Leaves generally crowded at stem tips; middle and upper 3 per whorl; blade generally 9–15 mm, 1.5–3 mm wide, linear, tip obtuse or abruptly pointed
Staminate inflorescence: bract ovoid to elliptic, swollen; flower not deciduous, not free-floating
Staminate flower: sepals 3.5–5 mm, ± 4 mm wide; petals ± 5 mm
Pistillate flower: sepals ± 2–3 mm
Seed glabrous
Chromosomes: 2n=24,48
Ecology: Shallow water, ditches, sloughs, ponds, lakes
Elevation: 300–2600 m.
Bioregional distribution: Outer North Coast Ranges, High Cascade Range, High Sierra Nevada, Great Central Valley, San Francisco Bay Area, San Gabriel Mountains, San Bernardino Mountains, Great Basin Floristic Province
Distribution outside California: to British Columbia, e US; naturalized in Europe
Flowering time: Jul–Aug