Callitriche stagnalis
Pond water starwort
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Family: Plantaginaceae · Type: Herb · Not Native
Callitriche stagnalis (Pond water starwort) is a non-native California herb in the Plantaginaceae family, recognized by non-native status and distinctive bracts.
Pond water starwort is a naturalized perennial found in northern California Coast, northern California Coast Ranges, and northern Sierra Nevada Foothills in permanent water, muddy stream edges, and pond habitats at elevations below 800 meters. Flowering from April to June, this plant produces small, inconspicuous white flowers in delicate rosettes. Growing as a floating or terrestrial plant with slender stems, it forms compact clusters in aquatic environments. Its leaves are variable, ranging from 4 to 9 millimeters long and 1 to 4 millimeters wide, with translucent sickle-shaped bracts surrounding the tiny flowers. The fruit is light brown to gray, subsessile, with a wing that gradually transitions to the fruit wall.
Identification and appearance
Key characters: Co-occurs with 7 species; non-native status and distinctive bracts are diagnostic
Habitat and range
Habitat: Floating rosettes in permanent water, terrestrial on mud or becoming stranded by streams, or ponds
Elevation: < 800 m
Outside California: western and eastern North America, native to Europe
Bloom period
Callitriche stagnalis blooms Apr-Jun.
How to tell it apart
vs Nasturtium: Nasturtium has bright yellow or white 4-petaled flowers; Callitriche has no petals, just tiny styles.; vs Lemna: Lemna is free-floating duckweed with no roots in substrate; Callitriche is rooted with opposite-leaved stems.; vs Ludwigia: Ludwigia has showy yellow flowers and consistent leaf shape; Callitriche lacks petals and has dimorphic leaves.; vs Soleirolia: Soleirolia is terrestrial with round leaves; Callitriche is aquatic with narrow or spoon-shaped leaves.; vs Stellaria: Stellaria has notched white petals on terrestrial plants; Callitriche lacks petals and forms aquatic rosettes.
Frequently asked questions
Is Callitriche stagnalis native to California?
No. Callitriche stagnalis is not native to California (recorded as not native).
When does Callitriche stagnalis bloom?
Callitriche stagnalis blooms Apr-Jun.
What plant family does Callitriche stagnalis belong to?
Callitriche stagnalis is in the Plantaginaceae family, genus Callitriche.
What habitat does Callitriche stagnalis grow in?
Callitriche stagnalis grows in Floating rosettes in permanent water, terrestrial on mud or becoming stranded by streams, or ponds.
Related species
Other California species in the same genus, family, or bioregion.
- Callitriche trochlearis — Effluent water starwort
- Callitriche fassettii — Fassett's water starwort
- Callitriche heterophylla — Varied leaved water starwort
- Callitriche heterophylla var. bolanderi — Bolander's water starwort
- Callitriche heterophylla var. heterophylla — Varied leaved water starwort
- Callitriche longipedunculata — Longstock water-starwort
- Collinsia antonina — San antonio collinsia
- Collinsia bartsiifolia — White blue eyed mary
- Collinsia bartsiifolia var. bartsiifolia — White blue eyed mary
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.