Equisetum ×ferrissii
Ferriss' horsetail, Ferriss' Horsetail
(c) Patrick Hacker, some rights reserved (CC BY), uploaded by Patrick Hacker · licence
Family: Equisetaceae · Type: Perennial · Native
Equisetum ×ferrissii (Ferriss' horsetail) is a native California perennial in the Equisetaceae family, recognized by white misshapen spores and hybrid sterility.
Ferriss' horsetail is a native perennial found in coastal, northern California, Klamath Ranges, Sierra Nevada, Central Valley, Central Western, Southern California, and Desert Mountain regions in moist, sandy or gravelly areas at elevations below 3,000 meters. This distinctive plant features green, unbranched stems growing 20 to 180 centimeters tall with prominent dark-banded sheaths 7 to 17 millimeters long. Growing in distinctive vertical clusters, it has a unique segmented structure with 14 to 32 deciduous or persistent teeth along its stem segments. Its horsetail-like stems are characterized by pronounced green joints and a distinctive architectural form with uniform, closely spaced segments. The plant produces white spores in pointed cone-like structures, reflecting its ancient, prehistoric botanical lineage.
Identification and appearance
Key characters: 5 sympatric species; distinguished by white misshapen spores and hybrid sterility
Habitat and range
Habitat: Moist, sandy or gravelly areas
Elevation: < 3000 m
Outside California: to British Columbia, eastern United States
How to tell it apart
vs Foeniculum: Equisetum has scale-like leaves in whorls; Fennel has feathery, thread-like leaf divisions.; vs Hippuris: Equisetum has fused scale-like leaves at joints; Hippuris has separate linear leaves in whorls.; vs Juncus: Equisetum stems have distinct joints with leaf whorls; Juncus stems are smooth without joints.; vs Elegia: Equisetum stems are rough and hollow with whorled scales; Elegia has smooth stems with overlapping leaf sheaths.; vs Pinus: Equisetum is an herbaceous plant with jointed stems; Pine is a woody tree with needle clusters.
Frequently asked questions
Is Equisetum ×ferrissii native to California?
Yes. Equisetum ×ferrissii is native to California (recorded as native).
What plant family does Equisetum ×ferrissii belong to?
Equisetum ×ferrissii is in the Equisetaceae family, genus Equisetum.
What habitat does Equisetum ×ferrissii grow in?
Equisetum ×ferrissii grows in Moist, sandy or gravelly areas.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos
Last updated 2026-09-30
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.