Oxytheca watsonii
Watson's oxytheca
(c) Matt Berger, some rights reserved (CC BY), uploaded by Matt Berger · licence
Family: Polygonaceae · Type: Herb · Native
Conservation status: CNPS 2B.2
Oxytheca watsonii (Watson's oxytheca) is a native California herb in the Polygonaceae family, recognized by . CNPS Rank 2B.2, very limited range.
Watson's oxytheca is a rare (CNPS 2B.2) California native annual found in the southeastern White and Inyo Mountains, specifically in the Santa Rosa Hills of Inyo County, growing in sandy habitats at elevations of 1,200 to 2,000 meters. Flowering from June to October, this plant produces delicate white to pink flowers measuring 1 to 1.5 millimeters long in small clusters with distinctive reddish involucre awns about 2.5 to 3 millimeters long. Growing with erect to spreading stems 5 to 25 centimeters tall and 4 to 40 millimeters in diameter, the plant has a variable, open growth structure. Its leaves are small, measuring 7 to 40 millimeters long and 1 to 12 millimeters wide, with hairy and glandular surfaces on the upper side and smoother undersides. The plant's inflorescence features three free bracts with short awns, creating a unique and delicate botanical appearance.
Identification and appearance
Key characters: Geographically isolated. CNPS Rank 2B.2, very limited range
Habitat and range
Habitat: Sand
Elevation: 1200-2000 m
California counties: Inyo, San Bernardino
Outside California: Nevada
Bloom period
Oxytheca watsonii blooms Jun-Oct.
Conservation status
CNPS 2B.2
How to tell it apart
vs Eriogonum: Oxytheca has cup-like involucres with 3-4 awns; Eriogonum has larger, awnless involucres.; vs Mucronea: Oxytheca has 3-4 awns per involucre; Mucronea has different involucre structure.; vs Claytonia: Oxytheca is in Polygonaceae with awned involucres; Claytonia is in Montiaceae with no involucres.; vs Sidotheca: Oxytheca has smooth-edged petals; Sidotheca has fringed or 3-lobed petals.; vs Acanthoscyphus: Oxytheca has 3-5 awns per involucre; Acanthoscyphus has 7-30+ awns creating bristly appearance.
Frequently asked questions
Is Oxytheca watsonii native to California?
Yes. Oxytheca watsonii is native to California (recorded as native).
When does Oxytheca watsonii bloom?
Oxytheca watsonii blooms Jun-Oct.
Where in California does Oxytheca watsonii grow?
Oxytheca watsonii occurs in Inyo, San Bernardino, at elevations of 1200-2000 m.
What plant family does Oxytheca watsonii belong to?
Oxytheca watsonii is in the Polygonaceae family, genus Oxytheca.
Is Oxytheca watsonii rare or endangered?
Oxytheca watsonii carries California Rare Plant Rank 2B.2, state rank S1.
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.