Hymenothrix loomisii
Loomis' thimblehead
(c) Matt Berger, some rights reserved (CC BY) · licence
Family: Asteraceae · Type: Herb · Not Native
Hymenothrix loomisii (Loomis' thimblehead) is a non-native California herb in the Asteraceae family, recognized by habitat, elevation, and discoid heads with cream corollas.
Loomis' thimblehead is a naturalized plant found in the Sierra Nevada Foothills and southwestern California in disturbed sites at elevations below 1,000 meters. Flowering from July to October, this plant produces cream-colored disk flowers in heads with linear bracts and no ray flowers. Growing up to 1.5 meters tall with openly branched stems that are glabrous or minutely strigose, it has a distinctive appearance. Its leaves are uniquely dissected into narrow linear segments 1 to 2 millimeters wide, creating a delicate, finely textured foliage. The fruit is 3 to 5 millimeters long with small pappus scales that add to its intricate botanical structure.
Identification and appearance
Key characters: 2 sympatric species; distinguished by habitat, elevation, and discoid heads with cream corollas
Habitat and range
Habitat: Disturbed sites
Elevation: < 1000 m
Outside California: native to Arizona
Bloom period
Hymenothrix loomisii blooms Jul-Oct.
How to tell it apart
vs Palafoxia: Palafoxia has all-green phyllaries without scarious margins; Hymenothrix has brown-purple papery-edged bracts.; vs Arnica: Arnica has opposite leaves and yellow ray flowers; Hymenothrix has alternate leaves and no ray flowers.; vs Trichoptilium: Trichoptilium has feathery pappus bristles; Hymenothrix has scales tipped with single bristles.; vs Chaenactis: Chaenactis has blunt pappus scales; Hymenothrix has bristle-tipped pappus scales.; vs Carlquistia: Carlquistia is a low cushion shrub; Hymenothrix is an upright herbaceous perennial.
Frequently asked questions
Is Hymenothrix loomisii native to California?
No. Hymenothrix loomisii is not native to California (recorded as not native).
When does Hymenothrix loomisii bloom?
Hymenothrix loomisii blooms Jul-Oct.
What plant family does Hymenothrix loomisii belong to?
Hymenothrix loomisii is in the Asteraceae family, genus Hymenothrix.
What habitat does Hymenothrix loomisii grow in?
Hymenothrix loomisii grows in Disturbed sites.
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.