Sonchus arvensis subsp. uliginosus
Photo: parent species Sonchus arvensis · (c) Dmitriy Bochkov, some rights reserved (CC BY), uploaded by Dmitriy Bochkov · licence
Family: Asteraceae · Type: Herb · Not Native
Sonchus arvensis subsp. uliginosus is a non-native California herb in the Asteraceae family, recognized by distinguished primarily by perennial vs annual habit.
Marsh sow thistle is a naturalized perennial found in the northwestern Monterey Peninsula and southern Central Coast in damp soil environments at elevations below 1,800 meters. Flowering from March to June, this plant produces yellow flowers in heads with distinctive glandular peduncles and phyllaries. Growing with stems that feature sessile glandular hairs, it forms clusters in wet, marshy areas. Its leaves are likely elongated and deeply lobed, typical of the sow thistle genus. The plant represents an introduced species that has established itself in localized damp habitats along the California coast.
Identification and appearance
Key characters: 2 sympatric species; distinguished primarily by perennial vs annual habit
Habitat and range
Habitat: Uncommon. Damp soil
Elevation: < 1800 m
Outside California: North America, native to Europe
Bloom period
Sonchus arvensis subsp. uliginosus blooms Mar-Jun.
How to tell it apart
vs Taraxacum: Taraxacum has all basal leaves on leafless stalks, Sonchus has tall leafy branching stems.; vs Lactuca: Check seeds - Sonchus has no beak, Lactuca seeds have distinct neck before bristles.; vs Helminthotheca: Helminthotheca has spiny-bristly outer phyllaries creating a prickly appearance, Sonchus phyllaries are smooth.; vs Cirsium: Cirsium has spiny flower heads and disk flowers only, Sonchus has smooth heads with ray flowers.; vs Senecio: Senecio has yellow disk and ray flowers, Sonchus has only yellow ray flowers.
Frequently asked questions
Is Sonchus arvensis subsp. uliginosus native to California?
No. Sonchus arvensis subsp. uliginosus is not native to California (recorded as not native).
When does Sonchus arvensis subsp. uliginosus bloom?
Sonchus arvensis subsp. uliginosus blooms Mar-Jun.
What plant family does Sonchus arvensis subsp. uliginosus belong to?
Sonchus arvensis subsp. uliginosus is in the Asteraceae family, genus Sonchus.
What habitat does Sonchus arvensis subsp. uliginosus grow in?
Sonchus arvensis subsp. uliginosus grows in Uncommon. Damp soil.
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.