Sphaeropteris cooperi
Cooper's tree fern, Cooper's Tree Fern
(c) Tony Rebelo, some rights reserved (CC BY-SA) · licence
Family: Cyatheaceae · Type: Tree · Not Native
Sphaeropteris cooperi (Cooper's tree fern) is a non-native California tree in the Cyatheaceae family, recognized by Australian tree fern naturalized on Channel Islands, representing tropical fern family not native to California.
Cooper's tree fern is a naturalized tree found on Santa Catalina Island in coastal, open, rocky cliff environments at elevations below 220 meters. This large fern produces no flowers, instead displaying massive fronds up to 3.5 meters long with narrow-elliptic or lanceolate blade structures. Growing with a trunk less than 15 meters tall and 10 to 15 centimeters in diameter, it develops dramatic feather-like leaves with distinctive basal scales that are white or tan and translucent. Its fronds are complex and intricate, with pinnae up to 65 centimeters long and pinnules that are pinnately lobed almost to the midribs, creating an elaborate, layered appearance. The fern's leaf structure is particularly notable for its bristle-like teeth along the margins and the mixture of pale translucent scales and shorter, dark bristle-like hairs at its base.
Identification and appearance
Key characters: Australian tree fern naturalized on Channel Islands, representing tropical fern family not native to California
Habitat and range
Habitat: Coastal, open, rocky cliff faces, in granitic or sedimentary sandstone soils in fog belt
Elevation: < 220 m
Outside California: Oregon, Hawaii, western Australia, native to eastern Australia
How to tell it apart
vs Dicksonia: Sphaeropteris stipe bases carry broad, pale, translucent scales; Dicksonia stipe bases are clothed in soft reddish hairs, not scales.; vs Woodwardia: Sphaeropteris grows a tall, erect trunk; Woodwardia is a trunkless ground fern spreading from a prostrate rhizome.; vs Dryopteris: Sphaeropteris fronds reach 2-3 m atop a woody trunk; Dryopteris fronds are much smaller and rise directly from a crown at ground level.; vs Struthiopteris: Sphaeropteris has huge, 2-3-pinnate fronds on a trunk; Struthiopteris forms a flat ground rosette of once-pinnate fronds.; vs Pteridium: Sphaeropteris carries a crown of fronds on a single erect trunk; bracken (Pteridium) spreads underground with scattered, solitary fronds and no trunk.
Frequently asked questions
Is Sphaeropteris cooperi native to California?
No. Sphaeropteris cooperi is not native to California (recorded as not native).
What plant family does Sphaeropteris cooperi belong to?
Sphaeropteris cooperi is in the Cyatheaceae family, genus Sphaeropteris.
What habitat does Sphaeropteris cooperi grow in?
Sphaeropteris cooperi grows in Coastal, open, rocky cliff faces, in granitic or sedimentary sandstone soils in fog belt.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · 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.