Chorizanthe polygonoides var. polygonoides
Knotweed spineflower, Knotweed Spineflower
Photo: parent species Chorizanthe polygonoides · (c) Matt Berger, some rights reserved (CC BY) · licence
Family: Polygonaceae · Type: Herb · Native
Chorizanthe polygonoides var. polygonoides (Knotweed spineflower) is a native California herb in the Polygonaceae family, recognized by green color and moderate spine length vs longispina.
Knotweed spineflower is a California native perennial found in northwestern California, the Cascade Range, northern Sierra Nevada foothills, Sacramento Valley, and central western California in sandy or gravelly areas at elevations of 100 to 1,500 meters. Flowering from April to June, this plant produces delicate white flowers with distinctive spiny involucre lobes about 2 to 2.5 millimeters long. Growing with generally green stems and a relatively low, spreading habit, it forms compact clusters across open sandy terrain. Its leaves are small and compact, contributing to the plant's understated yet intricate appearance. The plant's notable chromosomal count of 20 suggests a stable genetic structure typical of its species.
Identification and appearance
Key characters: 24 sympatric species; green color and moderate spine length vs longispina
Habitat and range
Habitat: Sand or gravel
Elevation: 100-1500 m
California counties: Sonoma, Modoc, Lake, Nevada, Stanislaus, Tehama, Napa, Marin, Santa Barbara, Butte, Solano, Tuolumne, Amador, El Dorado, Sacramento, San Diego, San Luis Obispo, Santa Clara, Calaveras, Mendocino, Shasta, Alameda, Riverside, San Joaquin, Monterey, Plumas
Bloom period
Chorizanthe polygonoides var. polygonoides blooms Apr-Jun.
How to tell it apart
vs Eriogonum: Chorizanthe has 1 flower per involucre; Eriogonum has multiple flowers per involucre.; vs Eremothera: Chorizanthe has 6-parted flowers in spiny cups; Eremothera has 4-petaled evening-primrose flowers.; vs Calyptridium: Chorizanthe has flowers in awned involucres; Calyptridium has naked flowers with papery sepals.; vs Lastarriaea: Chorizanthe has thin papery flowers; Lastarriaea has distinctly thick, leathery-textured flowers.; vs Navarretia: Chorizanthe is in Polygonaceae with 6-parted flowers; Navarretia is in Polemoniaceae with 5-lobed tubular flowers.
Frequently asked questions
Is Chorizanthe polygonoides var. polygonoides native to California?
Yes. Chorizanthe polygonoides var. polygonoides is native to California (recorded as native).
When does Chorizanthe polygonoides var. polygonoides bloom?
Chorizanthe polygonoides var. polygonoides blooms Apr-Jun.
Where in California does Chorizanthe polygonoides var. polygonoides grow?
Chorizanthe polygonoides var. polygonoides occurs in Sonoma, Modoc, Lake, Nevada, Stanislaus, Tehama, Napa, Marin and other counties, at elevations of 100-1500 m.
What plant family does Chorizanthe polygonoides var. polygonoides belong to?
Chorizanthe polygonoides var. polygonoides is in the Polygonaceae family, genus Chorizanthe.
What habitat does Chorizanthe polygonoides var. polygonoides grow in?
Chorizanthe polygonoides var. polygonoides grows in Sand or gravel.
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.