California Polypody

Polypodium californicum
NATIVE

This fern emerges gracefully from its underground rhizome with the first winter rains. Its name, Polypody, reflects the way its fronds sprout from multiple points along a creeping rhizome. Look for the fronds on the vertical face of moss-covered rocks.

Description (Jepson, PlantID.net)

• Fern (Polypodiopsida) 
  • Ferns are a group of vascular plants that produce spores (reproductive cells)
    • Produce no flowers or seeds
    • Fossil records date back almost 400 million years, versus 130 million years for flowering plants
• Polypody Family (Polypodiaceae)
• Perennial herb
  • Summer deciduous
  • Grows from rhizomes (horizontal underground stems)
• Fronds
  • Deeply lobed (pinnatifid) or compound (divided into leaflets), with 1 level of division (1-pinnate)
  • Leaflets are finger-like
    • Fleshy to leathery, with serrate margins
    • Division incomplete (pinnatifid) with leaflet tissue continuous along the midrib
• Sori
  • Sori (singular: sorus) are clusters of spore-producing, sac-like structures called sporangia (singular: sporangium)
    • Sporangia sacs split open to catapult mature, microscopic spores, which are wind dispersed
  • Located on the underside of leaflets in parallel rows, either side of the midrib
  • Have no indusium (plural: indusia), a tissue flap sometimes covering sori

Distribution

• Native to California
  • Grows on coastal bluffs, in chaparral and mixed evergreen forests, in shaded canyons, along streambanks, north-facing slopes, roadcuts, and cliffs
  • See Calflora for statewide observations of this plant
• Outside California, grows in Baja California, Mexico, but confined to western North America
• Grows at elevations to 5,000 ft.

Uses (San Mateo County Parks prohibits removal of any natural material)

• Native people
  • Juice of the roots used as a rub for rheumatism and on sores as an antibiotic
  • Infusion of roots used as an eyewash

Name Derivation

• Polypodium (Pol-ee-PODE-ee-um) – from the Greek poly, “many,” and pod, “foot,” because the fronds rise from many points along the creeping rhizome

Notes

• Each sporangium sac contains around 60 spores, and each sorus cluster has about 60 sporangia: that’s about 3,600 spores per yellow dot! (Walters 2013)
• Watch this short video showing fern reproduction in action (KQED 2024)

ID Tips

• May be confused with western sword fern (Polystichum munitum), the only other fern at Edgewood whose fronds have one level of division, but western sword fern is not found trailside at Edgewood

At Edgewood

• Found in woodlands
  • Look for it on the boulder at the Sylvan trail waterfall
  • See iNaturalist for observations of this plant

Specific References

American Fern Society. About Ferns. Resources.

KQED San Francisco. 2024, April 16. Watch ferns get freaky [Video]. Deep Look. YouTube. 

Pai, A. 2018, Dec. 28. Fantastic ferns and where to find them. Bay Nature.

U.S. Forest Service. What are ferns? Forest Service. United States Department of Agriculture.

Walters, D. 2013. Polypody californicum: Common polypody or California polypody. CNPS-SLO. California Native Plant Society-San Luis Obispo.

General References

Calflora Database. 2014. Berkeley, California.

Calscape. 2018. California Native Plant Society.

Charters, M.L. 2015. California Plant Names: Latin and Greek Meanings and Derivations.

Charters, M.L. 2017. Southern California Wildflowers: Guide to the Pronunciation of Specific, Generic and Family Names.

Corelli, T. 2004. Flowering Plants of Edgewood Natural Preserve (2nd. ed.). Monocot Press, Half Moon Bay, California.

Dave’s Garden.

Elpel, T.J. 2013. Botany in a Day: The Patterns Method of Plant Identification. HOPS Press, Pony, Montana.

Flora of North America. efloras.org.

Harris, J.G., and M.W. Harris. 2013. Plant Identification Terminology: An Illustrated Glossary. Spring Lake Publishing, Spring Lake, Utah.

Keator, G. 2009. California Plant Families. University of California Press, Berkeley and Los Angeles, California.

Native American Ethnobotany DB.

Regents of the University of California. Jepson eFlora. Jepson Herbarium. University of California, Berkeley.