Alyssum simplex
Alyssum
(c) Steve Matson, some rights reserved (CC BY) · licence
Family: Brassicaceae · Type: Herb · Not Native
Alyssum simplex (Alyssum) is a non-native California herb in the Brassicaceae family, recognized by (A. desertorum). Key differences: larger size, coarsely stellate hairy fruits, winged toothed filaments.
Alyssum is a naturalized perennial found in northern and southern coastal ranges of California and the Modoc Plateau in open rangelands, foothills, and roadsides at elevations of 1,000 to 1,500 meters. Flowering from April to July, this plant produces light yellow flowers with petals 2 to 3.5 millimeters long. Growing with erect or sometimes decumbent stems 30 to 40 centimeters tall, it has distinctive stellate (star-shaped) hairs covering its surface. Its leaves are covered with coarse, appressed stellate hairs, giving the plant a distinctive textured appearance. The fruit is round, 4 to 6.5 millimeters long, with spreading stellate hairs and a short hairy style.
Identification and appearance
Key characters: 1 sympatric species (A. desertorum). Key differences: larger size, coarsely stellate hairy fruits, winged toothed filaments.
Habitat and range
Habitat: Roadsides, foothills, open rangeland
Elevation: 1000-1500 m
California counties: Kern, Nevada, Modoc, Shasta, San Benito, Glenn, Lassen, Yolo
Outside California: to Montana, Wyoming, northern Mexico, native to Europe, central and southwestern Asia, northern Africa
Bloom period
Alyssum simplex blooms Apr-Jul.
How to tell it apart
vs Lepidium: Alyssum has yellow flowers and star-shaped hairs; Lepidium has white flowers and simple hairs, pods often notched at tip.; vs Lobularia: Alyssum has yellow flowers and star-shaped hairs; Lobularia has white/purple flowers and distinctive two-pronged fork-like hairs.; vs Dithyrea: Alyssum has tiny yellow petals (1.5-4mm); Dithyrea has huge white petals (10-15mm) and spectacle-shaped fruits.; vs Euclidium: Alyssum fruits are flat and disc-like when developing; Euclidium fruits are plump and three-dimensional from the start.; vs Aubrieta: Alyssum is annual with short style (under 2mm); Aubrieta is perennial with very long style (4-12mm).
Frequently asked questions
Is Alyssum simplex native to California?
No. Alyssum simplex is not native to California (recorded as not native).
When does Alyssum simplex bloom?
Alyssum simplex blooms Apr-Jul.
Where in California does Alyssum simplex grow?
Alyssum simplex occurs in Kern, Nevada, Modoc, Shasta, San Benito, Glenn, Lassen, Yolo, at elevations of 1000-1500 m.
What plant family does Alyssum simplex belong to?
Alyssum simplex is in the Brassicaceae family, genus Alyssum.
What habitat does Alyssum simplex grow in?
Alyssum simplex grows in Roadsides, foothills, open rangeland.
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.