Najas marina
Holly-leaved water-nymph, Holly-Leaved Water-Nymph
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Family: Hydrocharitaceae · Type: Herb · Native
Najas marina (Holly-leaved water-nymph) is a native California herb in the Hydrocharitaceae family, recognized by unique prickled stems and low tooth count.
Holly-leaved water-nymph is a California native annual found in northern Coast Ranges, southern Sierra Nevada foothills, central Coast, southern Coast Ranges, southern California, San Bernardino Mountains, Peninsular Ranges, and deserts in ponds, lakes, marshes, and rivers at elevations below 1,000 meters. Flowering from July to August, this aquatic plant produces small flowers with delicate stamens and stigmas. Growing submerged with slender stems that are generally prickled between leaf segments, it forms dense underwater clusters. Its leaves have serrated margins with 8 to 13 teeth on each side, terminating in a sharp acute tip with a single distinctive tooth. The seeds are small, ovate, and feature a pitted coat with a dull surface.
Identification and appearance
Key characters: 2 sympatric species; distinguished by unique prickled stems and low tooth count
Habitat and range
Habitat: Ponds, lakes, marshes, rivers
Elevation: < 1000 m
California counties: San Luis Obispo, Los Angeles, Imperial, San Diego, Riverside, San Bernardino, Santa Barbara, Alameda, Inyo, Kern, Fresno, Santa Cruz, Ventura, Napa, San Benito, Monterey, Merced
Outside California: to north-central United States, Baja California, Eurasia, Pacific islands
Bloom period
Najas marina blooms Jul-Aug.
How to tell it apart
vs Hydrilla: Najas leaves have obvious teeth along margins; Hydrilla has spiny bumps on the leaf midrib underneath.; vs Elodea: Najas leaves are arranged opposite or in whorls of many; Elodea has 2-3 leaves at stem base, 3-7 higher up.; vs Egeria: Najas has tiny leaves under 1.5 cm; Egeria leaves are much larger (1.2-4 cm long).; vs Ottelia: Najas is completely submerged with tiny flowers; Ottelia has floating leaves and showy white flowers above water.; vs Limnobium: Najas is fully submerged with narrow toothed leaves; Limnobium has round floating leaves on spongy stalks.
Frequently asked questions
Is Najas marina native to California?
Yes. Najas marina is native to California (recorded as native).
When does Najas marina bloom?
Najas marina blooms Jul-Aug.
Where in California does Najas marina grow?
Najas marina occurs in San Luis Obispo, Los Angeles, Imperial, San Diego, Riverside, San Bernardino, Santa Barbara, Alameda and other counties, at elevations of < 1000 m.
What plant family does Najas marina belong to?
Najas marina is in the Hydrocharitaceae family, genus Najas.
What habitat does Najas marina grow in?
Najas marina grows in Ponds, lakes, marshes, rivers.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.