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Scaly Male Fern
Dryopteris affinis
Coastal Woodfern
Dryopteris arguta
  (Kaulf.) Maxon
Spinulose Woodfern
Dryopteris carthusiana
  Owner:   C. Michael Hogan    

Coastal Woodfern on the banks of Yulupa Creek, Sonoma County
Coastal woodfern
Dryopteris arguta

C. Michael Hogan PhD
December 14, 2008

Coastal woodfern is widely distributed along the western coastal area of North America, especially in rocky, sloping, shaded areas. This fern is known to have been useful to Native Americans as a food and medicine, and has been confirmed by modern biochemists to be a powerful anti-microbial.

D. arguta occurs chiefly in coastal areas from the extreme south of British Columbia (including the southeastern extremity of Vancouver Island) to Monterey County in California. Less frequently, this species is found in coastal ravines as far south as Baja California. Although most readily found in the coastal ranges, the species also occurs as far inland at the Lava Beds National Park, Sequoia and Kings Canyon National Park, Pinnacles National Monument and Joshua Tree National Monument. Disjunctive populations are found in Arizona, particularly in moist ravines of Gila County's Sierra Ancha and in the Superstition Mountains and Queens Creek areas of Pinal County.

D. arguta has a robust woody rhizomal architecture. The species may be semi-dormant in the hot dry summers, (Hoshizaki) in parts of the range where rainfall is sufficiently low. Each individual plant has several fronds with lengths of 35 to 90 cm,.(Abrams) with widths of about one third the length. The lanceolate leaf blades are nearly as wide at the base as at the middle.(Kozloff) Petioles are approximately 30 percent of the length of the leaf, and they exhibit scattered brown scales.

The deeply concave thin indusia are so closely spaced that they almost entirely cover the sporangia, and the individual sori are sometimes reniform, when not quite circular. Leaf lobes terminate with two to five sharply spreading teeth, which sometimes terminate in bristle-like tips. Veins can be traced clearly to the terminal teeth. (Jepson) D. arguta is of similar appearance to the Bracken Fern, but exhibits prominent castaneous scales on its stems.(Munz) It is also similar to D. expansa, but leaves of D. arguta are not more than twice compound. (Beidleman)

D. arguta is frequently found along the rocky verges of streams, often in steep sided canyons. Common Northern California riparian understory associates include Toxicodendron diversilobum, Rubus parviflorus, Vaccinium ovatum, Rhamnus californica and Holodiscus discolor. Common fern associates are sword, goldback, maidenhair, coffee and venus hair fern. Wildflower associates include Trillium ovatum, Maianthemum racemosa and Prosartes hookeri. A gamut of forest types are suitable habitat including California oak woodland and mixed conifer-oak woodland. Specific common dominant tree associates are California Bay Laurel, Black Oak, (Hogan) Pacific Madrone, Big Leaf Maple and Coast Live Oak.

In the southernmost range of Baja Mexico common associates in the Mediterranean scrub (Rodriguez-Estrella) are Adiantum jordanii, Aesculus parryi, Daucus pussilus, Mimulus aridus, Camissonia lewisii and Hemizonia fasciculata.

D. arguta demonstrates antimicrobial efficacy, which is linked to the presence of acyl derivatives of phloroglucinols, which have been shown to paralyze intestinal parasites. The phloroglucinol molecules are representatives of para-aspidin, desaspidin and albaspidins. Generation of phloroglucinols is thought to occur via external glands on the leaves of the Coast Wood Fern. (Wollenweberc) In a related species, D.cristata, a root derived extract has been shown efficacious in expelling intestinal worms from mammals.

In prehistoric times the Ohlone and Costanoan peoples ate the rhizomes of the Coastal woodfern, while Yurok tribesmen utilized the fronds to clean meat. The Karok peoples are known to have used the fronds for eel cleaning and preparation. Costanoans also used this fern species as a hair shampooing agent, while Miwok peoples used the roots as an anti-hemorraghic Other Dryopteris species were used for similar food source and cosmetic uses. (Moerman) For example, the closely related D. expansa had rhizomes used for food by the Khallan tribe, who also used D. expansa for a shampoo. .

* Barbara Joe Hoshizaki, Robbin Craig Moran (2001) Fern Growers Manual'', Timber Press, 604 pp ISBN 0881924954
* LeRoy Abrams (1923) Illustrated Flora of the Pacific States: Vol. I: Ferns to Birthworts, Stanford University Press, 568 pages ISBN 0804700036
* Eugene N. Kozloff (2005) Plants of Western Oregon, Washington & British Columbia, Timber Press, 608 pages ISBN 0881927244
* T.H. Kearney, Robert H. Peebles, Elizabeth McClintock (1940) Arizona Flora, University of California Press, ISBN 0520006372
* Jepson Manual (1993) University of California Press, Berkeley, California
* Philip Alexander Munz, Phyllis M. Faber, Dianne Lake (2003) Introduction to California Mountain Wildflowers, University of California Press, 247 pages ISBN 0520236351
* Linda H. Beidleman, Eugene N. Kozloff (2003) Plants of the San Francisco Bay Region: Mendocino to Monterey, University of California Press, 504 pages ISBN 0520231732
* Ricardo Rodriguez-Estrella (2005) Terrestrial Birds and Conservation Priorities in Baja California Peninsula, U.S.Forest Service General Tech.Rep.PSW-GTR 191, pp 115-120
* Daniel E. Moerman (1998) Native American Ethnobotany, Timber Press, 927 pages ISBN 0881924539
* C.Michael Hogan (2008) Black Oak: Quercus kelloggii, Globaltwitcher.com, ed. Nicklas Stromberg
* Eckhard Wollenweberc, Jan F. Stevensa, Monika Ivanicb and Max L. Deinze (1998) Acylphloroglucinols and flavonoid aglycones produced by external glands on the leaves of two dryopteris ferns and currania robertiana, Phytochemistry, volume 48, issue 6, pages 931-939
* J.T.Kartesz (1994). A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, Oregon