Callitriche longipedunculata
Longstock water-starwort
Family: Plantaginaceae · Type: Herb · Native
Callitriche longipedunculata (Longstock water-starwort) is a native California herb in the Plantaginaceae family, recognized by long peduncles are highly diagnostic.
Longstock water-starwort is a California native perennial found in the northern Coast Ranges, California Freshwater, Great Valley, San Francisco Bay Area, and western Peninsular Ranges in vernal pools and shallow water habitats at elevations below 625 meters. Flowering from March to May, this aquatic plant produces tiny, inconspicuous flowers nestled among spoon-shaped leaves. Growing as a delicate, submersed or stranded aquatic plant with slender stems, it develops compact clusters of leaves that gradually narrow to thin petioles. Its leaves are small, measuring 2.8 to 5 millimeters long and 1.8 to 3.3 millimeters wide, with a distinctive spoon-like shape that helps it adapt to fluctuating water environments. The fruit is small and dark, with narrow wings extending from tip to base and peduncles ranging from 2 to 25 millimeters long.
Identification and appearance
Key characters: Co-occurs with 7 species; long peduncles are highly diagnostic
Habitat and range
Habitat: Becoming stranded or submersed in vernal pools
Elevation: < 625 m
Bloom period
Callitriche longipedunculata blooms Mar-May.
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 longipedunculata native to California?
Yes. Callitriche longipedunculata is native to California (recorded as native).
When does Callitriche longipedunculata bloom?
Callitriche longipedunculata blooms Mar-May.
What plant family does Callitriche longipedunculata belong to?
Callitriche longipedunculata is in the Plantaginaceae family, genus Callitriche.
What habitat does Callitriche longipedunculata grow in?
Callitriche longipedunculata grows in Becoming stranded or submersed in vernal pools.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · 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.