Polystichum imbricans subsp. curtum
Photo: parent species Polystichum imbricans · (c) Ed Alverson, some rights reserved (CC BY) · licence
Family: Dryopteridaceae · Type: Herb · Native
Polystichum imbricans subsp. curtum is a native California herb in the Dryopteridaceae family.
Rock sword fern is a California native perennial found in northern coastal California, high Cascade Range, northern and central Sierra Nevada, San Francisco Bay Area, southern coastal ranges, southern California, Transverse Ranges, and Peninsular Ranges in rocky woodland habitats at elevations of 400 to 1,600 meters. This fern features long fronds arranged in a single plane, with individual pinnae reaching 3 to 6 centimeters long. Growing with dark green, leathery fronds 15 to 80 centimeters tall, it forms dense, overlapping clusters in rocky crevices and slopes. Its pinnae are broadly lance-shaped, growing in a distinctive, orderly arrangement with submarginal spore clusters protected by slightly toothed indusia. The fern creates dense, evergreen patches in rocky woodland understories, providing shelter for small forest creatures.
Habitat and range
Habitat: Rocky slopes, crevices, woodland
Elevation: 400-1600 m
California counties: San Bernardino, Shasta, Riverside, San Diego, Santa Cruz, Orange, Los Angeles, Butte, Mariposa, Mendocino, Monterey, Ventura, Kern, Plumas, Yuba, El Dorado, San Luis Obispo, Lake, Nevada, Santa Clara, Santa Barbara, Trinity, Tehama, Colusa, Placer, Siskiyou, Humboldt, Del Norte
How to tell it apart
vs Nephrolepis: Polystichum has bristle-tipped teeth and grows in wild habitats; Boston fern has smooth-edged leaflets and escapes from cultivation.; vs Dryopteris: Polystichum fronds feel prickly with bristle-tipped teeth; Dryopteris fronds feel smooth without bristles.; vs Polypodium: Polystichum has shield-shaped spore covers and bristly edges; polypody has naked round spore dots and smooth margins.; vs Struthiopteris: Polystichum has one frond type with bristly teeth; ostrich fern has separate narrow fertile fronds and smooth sterile ones.; vs Athyrium: Polystichum feels prickly and has shield-shaped spore covers; lady ferns feel soft with curved, elongated spore clusters.
Frequently asked questions
Is Polystichum imbricans subsp. curtum native to California?
Yes. Polystichum imbricans subsp. curtum is native to California (recorded as native).
Where in California does Polystichum imbricans subsp. curtum grow?
Polystichum imbricans subsp. curtum occurs in San Bernardino, Shasta, Riverside, San Diego, Santa Cruz, Orange, Los Angeles, Butte and other counties, at elevations of 400-1600 m.
What plant family does Polystichum imbricans subsp. curtum belong to?
Polystichum imbricans subsp. curtum is in the Dryopteridaceae family, genus Polystichum.
What habitat does Polystichum imbricans subsp. curtum grow in?
Polystichum imbricans subsp. curtum grows in Rocky slopes, crevices, woodland.
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.