Nemacaulis denudata
Cottonheads
(c) Trevor Van Loon, some rights reserved (CC BY) · licence
Family: Polygonaceae · Type: Herb · Native
Nemacaulis denudata (Cottonheads) is a native California herb in the Polygonaceae family, recognized by no sympatric species.
Cottonheads is a California native annual found in coastal sand dunes and coastal scrub habitats along the western California coast. Flowering from April to September, this delicate plant produces white to rose-colored flowers small and clustered in terminal cyme-like arrangements. Growing prostrate to erect with stems 4 to 25 centimeters tall and spreading up to 8 centimeters wide, it has a distinctively sprawling growth habit. Its linear leaves are narrow, measuring 1 to 8 centimeters long and only 0.1 to 1.5 centimeters wide, growing primarily at the plant's base. The tiny fruit is brown to deep maroon or black, measuring just 1 millimeter long with a curved embryo.
Identification and appearance
Key characters: Geographically isolated from all other species; no sympatric species
Habitat and range
California counties: San Bernardino, San Diego, San Luis Obispo
How to tell it apart
vs Lastarriaea: Nemacaulis has many spine-less bracts creating cottony heads; Lastarriaea has only 3 spine-tipped bracts.; vs Hollisteria: Nemacaulis has many spine-less bracts; Hollisteria has 3-4 spine-tipped bracts.; vs Johanneshowellia: Nemacaulis has many bracts creating cottony flower heads; Johanneshowellia has 4-7 bracts without the cottony appearance.
Frequently asked questions
Is Nemacaulis denudata native to California?
Yes. Nemacaulis denudata is native to California (recorded as native).
Where in California does Nemacaulis denudata grow?
Nemacaulis denudata occurs in San Bernardino, San Diego, San Luis Obispo.
What plant family does Nemacaulis denudata belong to?
Nemacaulis denudata is in the Polygonaceae family, genus Nemacaulis.
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.