Tonestus peirsonii
Peirson's tonestus, Peirson's Tonestus
(c) Martin Purdy, some rights reserved (CC BY) · licence
Family: Asteraceae · Type: Subshrub · Native
Conservation status: CNPS 4.3
Tonestus peirsonii (Peirson's tonestus) is a native California subshrub in the Asteraceae family, recognized by larger involucre, more rays, and higher elevation.
Peirson's tonestus is a rare California native (CNPS rank 4.3) perennial found in central Sierra Nevada Mountains in Inyo and Fresno counties, particularly in rocky granite sites and crevices at elevations of 2,900 to 3,700 meters. Flowering from July to August, this plant produces white ray flowers with yellow disk centers in compact heads 14 to 28 millimeters wide. Growing in dense clusters with a branched woody base, it forms low-growing plants less than 20 centimeters tall. Its leaves range up to 8 centimeters long, with coarse serrations or nearly smooth edges, arranged in a compact cluster. The plant produces hairy fruits 2.5 to 6 millimeters long, with inner flower bracts that are green to reddish at the tips.
Identification and appearance
Key characters: 1 sympatric species; distinguished by larger involucre, more rays, and higher elevation
Habitat and range
Habitat: Rocky sites, crevices in granite
Elevation: 2900-3700 m
Bloom period
Tonestus peirsonii blooms Jul-Aug.
Conservation status
CNPS 4.3
How to tell it apart
vs Solidago: Tonestus is sticky-glandular; Solidago is non-sticky with smooth or slightly hairy texture.; vs Xanthisma: Tonestus foliage is sticky not spiny; Xanthisma leaves have spine-tipped teeth.; vs Pyrrocoma: Tonestus is sticky-glandular throughout; Pyrrocoma lacks stalked glands and sticky texture.; vs Petradoria: Tonestus has basal leaf rosette; Petradoria is woody shrub without basal rosette.; vs Euthamia: Tonestus is sticky with large solitary heads; Euthamia is non-sticky with small clustered heads.
Frequently asked questions
Is Tonestus peirsonii native to California?
Yes. Tonestus peirsonii is native to California (recorded as native).
When does Tonestus peirsonii bloom?
Tonestus peirsonii blooms Jul-Aug.
What plant family does Tonestus peirsonii belong to?
Tonestus peirsonii is in the Asteraceae family, genus Tonestus.
Is Tonestus peirsonii rare or endangered?
Tonestus peirsonii carries California Rare Plant Rank 4.3, state rank S3.
What habitat does Tonestus peirsonii grow in?
Tonestus peirsonii grows in Rocky sites, crevices in granite.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CNPS Rare Plant Inventory · Index of California Plant Names · CalPhotos · CDFW CNDDB
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.