Calycoseris wrightii
White tack-stem
Photo by Chez Brungraber
Family: Asteraceae · Type: Herb · Native
Calycoseris wrightii (White tack-stem) is a native California herb in the Asteraceae family, recognized by flower color, fruit color/texture, and habitat preference.
White tack-stem is a California native annual found in the Mojave Desert and Inyo Mountains on desert plains, pavement, washes, and gravelly slopes at elevations of 100 to 1,600 meters. Flowering from March to May, this plant produces white flowers with fine reddish veins on the back of ligules that are 2 to 3 centimeters long. Growing with delicate stems reaching up to 15 centimeters tall, it forms a distinctive low-spreading habit across desert landscapes. Its basal leaves extend 6 to 15 centimeters long, creating a rosette-like arrangement at the plant's base. The fruit is dark brown with roughened surfaces and distinctive tubercled ribs, developing a pappus 5 to 6.5 millimeters long.
Identification and appearance
Key characters: 1 sympatric species; flower color, fruit color/texture, and habitat preference are diagnostic
Habitat and range
Habitat: Desert plains, pavement, washes, gravelly slopes
Elevation: 100-1600 m
Outside California: to Utah, Texas, northwestern Mexico
Bloom period
Calycoseris wrightii blooms Mar-May.
How to tell it apart
vs Rafinesquia: Rafinesquia pappus stays attached; Calycoseris pappus mostly falls away when mature.; vs Malacothrix: Malacothrix seeds lack beaks; Calycoseris seeds taper into short beaks.; vs Anisocoma: Anisocoma has scale-like pappus; Calycoseris has bristly pappus that mostly falls off.; vs Munzothamnus: Munzothamnus is a woody shrub; Calycoseris is a desert annual herb.; vs Hieracium: Hieracium is densely long-hairy; Calycoseris has glandular-sticky stems without long hairs.
Frequently asked questions
Is Calycoseris wrightii native to California?
Yes. Calycoseris wrightii is native to California (recorded as native).
When does Calycoseris wrightii bloom?
Calycoseris wrightii blooms Mar-May.
What plant family does Calycoseris wrightii belong to?
Calycoseris wrightii is in the Asteraceae family, genus Calycoseris.
What habitat does Calycoseris wrightii grow in?
Calycoseris wrightii grows in Desert plains, pavement, washes, gravelly slopes.
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.