Tripleurospermum inodorum
Scentless mayweed, false chamomile, False Chamomile
(c) Rob Hille, some rights reserved (CC BY-SA) · licence
Family: Asteraceae · Type: Annual · Not Native
Tripleurospermum inodorum (Scentless mayweed) is a non-native California annual in the Asteraceae family, recognized by Introduced Eurasian species; distinguished from related genera by lack of fragrance and fruit morphology.
Scentless mayweed is a naturalized annual found in the North Coast and California Ranges in disturbed sites and roadsides at elevations below 1,500 meters. Flowering from May to August, this plant produces white ray flowers in daisy-like heads 3 to 4.5 centimeters wide, with rays becoming reflexed as they mature. Growing with glabrous or sparsely hairy stems 30 to 60 centimeters tall, it spreads readily in disturbed landscapes. Its finely divided leaves feature delicate, thread-like segments up to 8 centimeters long, giving the plant a feathery appearance. The fruit is approximately 2 millimeters long with distinctive white ribs and small resin glands.
Identification and appearance
Key characters: Introduced Eurasian species; distinguished from related genera by lack of fragrance and fruit morphology
Habitat and range
Habitat: Disturbed sites, roadsides
Elevation: < 1500 m
Outside California: to eastern North America, native to Eurasia
Bloom period
Tripleurospermum inodorum blooms May-Aug.
How to tell it apart
vs Anthemis: Anthemis has a distinct scent when crushed; Tripleurospermum is completely scentless.; vs Mauranthemum: Mauranthemum has simple toothed or lobed leaves; Tripleurospermum has finely dissected thread-like segments.; vs Leucanthemum: Leucanthemum has much larger flower heads (6-9 cm) and simple leaves; Tripleurospermum has smaller heads with thread-like leaves.; vs Argyranthemum: Argyranthemum has a woody base you can feel; Tripleurospermum is herbaceous with soft stems.
Frequently asked questions
Is Tripleurospermum inodorum native to California?
No. Tripleurospermum inodorum is not native to California (recorded as not native).
When does Tripleurospermum inodorum bloom?
Tripleurospermum inodorum blooms May-Aug.
What plant family does Tripleurospermum inodorum belong to?
Tripleurospermum inodorum is in the Asteraceae family, genus Tripleurospermum.
What habitat does Tripleurospermum inodorum grow in?
Tripleurospermum inodorum grows in Disturbed sites, roadsides.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos
Last updated 2026-09-30
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.