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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.



Robert F. Thorne

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.


Annual, aquatic, submersed, sometimes mat-like, monoecious or dioecious
Stems several, much-branched, slender
Leaves simple, cauline, opposite or appearing ± whorled; sheath generally wider than blade, expanded abruptly at junction with blade; blade generally linear, margin entire to spiny
Inflorescence axillary; flowers 1–few, clustered, inconspicuous
Staminate flower: perianth 0; stamen 1, anther opening irregularly, subsessile, subtended by 2 minute involucres, inner membranous, flask-shaped, outer cup-like, tubular, or with free scales
Pistillate flower: perianth part 0–1; ovary 1, chamber 1, ovule 1, style short, stigmas 2–4, linear
Fruit: achene, fusiform; outer wall thin, ± translucent
Species in genus: ± 50 species: ± worldwide
Etymology: (Greek: water nymph)
Reference: [Shaffer-Fehre 1991 Bot J Linn Soc 107:189–209]


N. marina L.


Stem < 4 dm, branched from base; internodes often minutely spiny
Leaves 1–4 cm, 1–3 mm wide, ± evenly spaced, stiff; sheath rounded at junction with blade, entire or minutely few-toothed; blade margin and lower surface coarsely spine-toothed
Staminate flower 3–4 mm; anther 4-chambered
Pistillate flower 3–4 mm; stigmas 3
Fruit: surface smooth (finely net-like at 20X magnification)
Ecology: Ponds, lakes, marshes, rivers
Elevation: < 1000 m.
Bioregional distribution: North Coast Ranges, s Sierra Nevada Foothills, Central Coast, South Coast Ranges, South Coast, San Bernardino Mountains, Peninsular Ranges, Desert
Distribution outside California: to north-central US, Baja California, Eurasia, Pacific islands
Flowering time: Jul–Aug

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