Category Archives: Ferns

Giant Chain Fern, Woodwardia fimbriata

Giant Chain Fern                                          Chain Fern family–Blechnaceae

Woodwardia fimbriata Sm.

(Wood-WAR-dee-uh  fim-bree-AH-tuh)

Names:    The genus is named after British botanist Thomas J. Woodward.  Chain Ferns get their common name from the chain-like rows of oblong sori on the undersides of the pinnae.  The species name, fimbriata means fringed, due to the margins having many tiny spines.  This species may also be called Western Chain Fern or Giant Chain Ferry.

Relationships:   There are about 14-20 species of Woodwardia in the northern hemisphere, with only 3 species in the U.S. and Canada.

Distribution of Giant Chain Fern from USDA Plants Database

Distribution: Giant Chain Fern has been found in Texada and Vancouver Islands in British Columbia, and in the Puget Sound region of Washington where it is listed as sensitive.  It is more common from southern Oregon and California to northwest Mexico, mostly near the coast, but can also be found inland in Arizona and Nevada.

Growth:  Fronds typically grow 1-5 feet (0.4-1.5 m) but may grow up to 9 feet (3m).

Habitat: Giant Chain Fern grows in mild, wet coastal forests. It is sometimes found growing on seepy coastal cliffs or in desert areas near shady seeps. Wetland designation: FACW, it usually occurs in wetlands, but is occasionally found in non-wetlands.

Diagnostic Characters:  Evergreen fronds grow upright or slightly bent, from a short, robust rhizome.  They are broadly feather-shaped with once-pinnate, deeply cut segments; margins having pointed teeth tipped with tiny spines.

In the Landscape:   About Woodwardia fimbriata, Hitchcock writes: “This is surely our choicest large fern.”  Being the largest, it is certainly the most impressive of all our ferns, it performs best in a woodland garden especially next to streams, bogs, springs or ponds, but it can also grow in full sun with adequate summer moisture.  It can be very striking as a focal point or when planted against a wall in a shady location.  It readily produces “sporeling plants” in wet areas.  It also may be propagated in the spring by division of the rhizomes–but judicious collection of spores is preferable where this species is rare.

Use by People:   Natives in California used the leaves for fiber to make baskets, and to line the top and bottom of an earth oven for baking acorn bread and other foods.

 Links:

USDA Plants Database

Consortium of Pacific Northwest Herbaria

WTU Herbarium Image Collection, Plants of Washington, Burke Museum

E-Flora BC, Electronic Atlas of the Flora of British Columbia

Jepson Eflora, University of California

Calphotos

Ladybird Johnson Wildflower Center

Native American Ethnobotany, University of Michigan, Dearborn

Deer Fern, Blechnum spicant

Deer Fern                                          Chain Fern family–Blechnaceae

Blechnum spicant (L.) Sm.

(BLEK-num SPEE-kant)

Names:  Blechnum comes from a general Greek name for fern.  Spicant means spiked referring to the erect fertile fronds.  Other common names include: Hard Fern or Rough Spleenwort.  It also has been known as Struthiopteris spicant.

Relationships: There are about 150-220 species of Blechnum (generally known as Hard Ferns or Midsorus Ferns) throughout the world, most are from tropical regions in the southern hemisphere, with just a few in the temperate regions of both hemispheres.  This genus spans the globe from the southern-most fern species, B. penna-marina, from Cape Horn to arctic regions in Iceland and Norway.  A few Ecuadorean species reach tree stature growing up to 3 meters tall.  Only two other species occur in the mainland United States (in the Gulf States & Florida)—these and 5 additional species also occur in Puerto Rico.

Distribution of Deer Fern from USDA Plants Database

Distribution: Deer Fern is found in Europe, northern Asia, Japan and in western North America from southern Alaska to the central California coast; mostly west of the Cascades, but it also is reaches east to the Idaho panhandle.

 

 

 

 

 

 

 

 

 

 

 

Fertile fronds emerging vertically from the center of the more horizontal sterile fronds.

Diagnostic Characters: Deer fern has two types of fronds: narrow, evergreen, once-pinnate (or deeply lobed), sterile leaves spread outward, growing 10-80 cm long; even narrower, taller (1-3 feet), fertile fronds grow erect, from the center, soon withering after spore dispersal.  The once-pinnate leaflets on the fertile fronds are much narrower and roll almost tube-like around the continuous sori.  Leaf stalks are a dark, purplish-brown, and grow from a short, thick rhizome.

Fertile fronds have edges that are rolled under.

 

 

 

 

 

 

 

 

 

 

Habitat: This species grows best in moist to wet forests and along streambanks. Wetland designation: FAC+, Facultative, it is equally likely to occur in wetlands or non-wetlands.

 

In the Landscape:  Hitchcock writes: Deer Fern “is a truly choice fern usable in many places in the garden, but so common as to have little appeal to most gardeners.”  That said, it is one of the best native ferns for landscapes, second only to Sword Fern.  Although at home in a woodland garden, it can adapt to many situations, given adequate shade and/or moisture. Deer Fern has also been used as a houseplant.

 

Use by People: The roots and young shoots were cooked and eaten as an emergency food; the young tender stems can also be peeled and the center portion eaten to relieve hunger; the leaves eaten to prevent thirst.  The leaflets have been chewed to treat cancer, lung disorders and stomach problems; and a decoction of the root to treat diarrhea.  The leaves were used medicinally on skin sores, which is said to have been learned by watching deer rub their antler stubs in this plant.  The fronds were also used to line pits for baking camas (along with Sword Fern) and have been used for bedding.

 

Use by wildlife:  Deer fern provides valuable forage for deer, Mountain Goat, Bighorn Sheep, elk, moose, and caribou.

Links:

USDA Plants Database

Consortium of Pacific Northwest Herbaria

WTU Herbarium Image Collection, Plants of Washington, Burke Museum

E-Flora BC, Electronic Atlas of the Flora of British Columbia

Jepson Eflora, University of California

Calphotos

Ladybird Johnson Wildflower Center

USDA Forest Service-Fire Effects Information System

Plants for a Future Database

Native American Ethnobotany, University of Michigan, Dearborn

Ostrich Fern, Matteuccia struthiopteris

Ostrich Fern                        USDA: The Wood Fern Family—Dryopteridaceae

                                        Newer classification: The Sensitive Fern Family—Onocleaceae

Matteuccia struthiopteris (L.) Todaro

(ma-TOO-kee-uh  stroo-thee-OP-ter-is)

Names: The genus is named after Carlo Matteucci an Italian physicist and pioneer in the study of bioelectricity.   Struthio is the ostrich genus; pteris means fern— the fronds resemble ostrich feathers.  It is also known as Shuttlecock Fern, because of the way the fronds grow in a clump, like the feathery tail of a badminton birdie!

Relationships:  Ostrich Fern is the only species in the genus Matteuccia.

Distribution of Ostrich Fern from USDA Plants Database

Distribution: It is found in many of the temperate regions in the northern hemisphere.  In North America, it is found throughout much of the northeast and across Canada; but only reaches the west coast in southern Alaska and British Columbia.  It is listed as rare, of special concern or vulnerable in Indiana, Rhode Island and New York.

 

 

 

Growth: Sterile, deciduous fronds grow to nearly 6 feet in moist, moderate climates.  In less than ideal conditions it is often much shorter, usually 1-5ft. (30-140cm). Ostrich Fern spreads by underground rhizomes to form new crowns and often grows in dense colonies, resistant to destruction by floodwaters.

Habitat: Ostrich Fern is hardy to extreme cold and is most often found in lowland or montane alluvial forests, riverbanks and sandbars.

Diagnostic Characters: The sterile, bright-green fronds grow nearly vertical in vase-like clusters.  They are broadest in the middle upper ¼ of the frond and are once-pinnate with deeply cut pinnae.  Brown, fertile fronds are shorter (60cm) and narrower, leaf tissue curling over the spore cases; they persist over winter, releasing spores in early spring.

In the Landscape: Ostrich Fern is a popular garden ornamental.  Although spectacularly beautiful in the early summer, it may start looking haggard later in the summer, depending on local conditions.  It prefers a moist, cool location protected from winds.  It is easily propagated by division.

Use by People: The fiddleheads are sometimes eaten raw, or cooked, most notably in Japan; the flavor is sometimes compared to asparagus.  As with all ferns, caution is advised, especially consuming raw parts.

Use by Wildlife: It is used as a food plant by the larvae of some moths.

Links:

USDA Plants Database

Consortium of Pacific Northwest Herbaria

E-Flora BC, Electronic Atlas of the Flora of British Columbia

Calphotos

Ladybird Johnson Wildflower Center

Plants for a Future Database

Native American Ethnobotany, University of Michigan, Dearborn

Oak Ferns, Gymnocarpium sp.

The Wood Fern Family—Dryopteridaceae

Western Oak Fern  Gymnocarpium dryopteris (L.) Newman   (jim-no-KARP-ee-um  dry-OP-ter-is)  (Tetraploid N-80)             &

Pacific Oak Fern  Gymnocarpium disjunctum (Rupr.) Ching   (jim-no-KARP-ee-um dis-junkt-um)    –Formerly considered a subspecies of G. dryopteris. (Diploid N=40)

Names:  Gymnocarpium means naked fruit because the spore cases are not covered with an indusium. The common name and specific epithet dryopteris refers to its similarity to the genus Dryopteris, (which literally means Oak (or Wood) Fern). Disjunctum refers to the separation of this species from G. dryopteris.

Relationships: There are only about 8 species of gymnocarpium, mostly in the temperate regions of the northern hemisphere.   Common names of G. dryopteris include Western or Northern Oak Fern.  Dryopteris disjuncta is a botanical synonym.  Many of the western forms appear to be diploid, as opposed to the European and eastern U.S. tetraploids, and are now often given the name, Pacific or Western Oak Fern, G. disjunctum (disjunct- means separated).

Distribution: G. dryopteris is distributed throughout the Northern Hemisphere, whereas G. disjunctum is confined to the coastal northwest of North America and the Pacific coast of Russia.  G. dryopteris is listed as endangered, threatened or vulnerable in Illinois, Maryland, Iowa, Ohio, Rhode Island, and New York.

Distribution of Western Oak Fern from USDA Plants Database

Distribution of Pacific Oak Fern from USDA Plants Database

Growth: Pacific Oak Fern is generally a larger plant than Western Oak Fern (10-40 cm vs. 5-25 cm long fronds), with more divided leaves and smaller spores.

It is hard to tell the difference between these two species and I admit I am not an expert, but I believe this is a Pacific Oak Fern.

Habitat:  In the Pacific Northwest, these ferns grow in shady, moist woods, streambanks and wet cliffs.  Despite its name, it is not usually found in association with oaks, preferring mixed coniferous forests.  Wetland designation: FAC, Facultative, it is equally likely to occur in wetlands or non-wetlands.

 

Diagnostic Characters: Although the fronds are most often born singly, they spread by rhizomes, forming large colonies.  The deciduous fronds are broadly triangular, 2-3 pinnate and hairless.  Spore cases are round and uncovered.

In the Landscape: Oak Ferns make a nice groundcover in a woodland garden; their lush, bright green fronds brighten a dark forest floor. They can be propagated by division.

Oak Fern and Vanilla Leaf on a forest floor.

Use by People: The presence of Oak Fern was a sign of water for the Okanagan tribe when travelling through the mountains.

Use by Wildlife: Grizzly Bear and Elk have been observed eating Oak Fern.

Links for Gymnocarpium dryopteris:

USDA Plants Database

Consortium of Pacific Northwest Herbaria

WTU Herbarium Image Collection, Plants of Washington, Burke Museum

E-Flora BC, Electronic Atlas of the Flora of British Columbia

Calphotos

Ladybird Johnson Wildflower Center

USDA Forest Service-Fire Effects Information System

Native Plants Network, Propagation Protocol Database

Native American Ethnobotany, University of Michigan, Dearborn

Links for Gymnocarpium disjunctum:

USDA Plants Database

Consortium of Pacific Northwest Herbaria

WTU Herbarium Image Collection, Plants of Washington, Burke Museum

E-Flora BC, Electronic Atlas of the Flora of British Columbia

Native American Ethnobotany, University of Michigan, Dearborn

 

Spreading Wood Fern, Dryopteris expansa

Spreading Wood Fern               The Wood Fern Family—Dryopteridaceae

Dryopteris expansa Adans.

(dry-OP-ter-is  ex-PAN-suh)

Names:  Dryo- comes from a Greek word meaning tree, or more specifically oak—the same root as is found in the words dryad and druid.  Pteris means fern.  Expansa means expanding or spreading.  Botanical synonyms include D. austriaca, D. assimilis, and D. dilatata.  This species is also known as Arching, Northern, Spiny, Redwood, or Creekbank Wood fern; Northern, Alpine or Broad Buckler Fern; or Shield Fern.

Relationships: There are about 250 Dryopteris sp. in the temperate northern hemisphere.  They are generally called Wood Ferns, Male Ferns, or Buckler Ferns.  Many are popular ornamentals.  About 18 species are found in the mainland United States, (several naturally occurring hybrids, too), about a dozen are native to Hawaii.

Distribution of Spreading Wood Fern from USDA Plants Database

Distribution: Spreading Wood Fern is native throughout much of the temperate regions in the northern hemisphere, from the subarctic to high altitudes in southern mountains.  In the U.S. it occurs from Alaska to northern California, mostly west of the Cascades in Washington and Oregon; it also is found spottily in the Rocky Mountain States, in the Great Lakes region, and eastern Canada.

Growth: Spreading Wood Fern grows to 3 feet (1m)

Habitat: It grows in moist forests, streambanks, and mountain slopes. Wetland designation: FACW, It usually occurs in wetlands, but is occasionally found in non-wetlands.

Diagnostic Characters: Deciduous fronds are usually clustered and erect to wide-spreading. They are triangular to oblong shaped; 2-3 pinnate.  The lowest pinnae pair are usually longer, triangular and asymmetrical.  Spore cases are rounded, on the undersides of pinnae.  The erect or ascending rhizome often produces offshoots, which may be divided.

In the Landscape: Spreading Wood Fern is easy to grow and its fine-textured, lacy leaves are ideal for a woodland garden.

Use by natives: Northwest natives ate the rhizomes, baking them in pits overnight.  Pounded roots were applied to cuts.  The leaves were soaked and used to wash hair.  Eskimos removed the chaffy covering and boiled the fiddleheads and ate them with seal oil and dried fish or in soups.  The root has been used to treat internal parasites, such as tape worms.

Use by Wildlife: Spreading Wood Fern is eaten in small amounts by Blue Grouse and Mountain Goats.  Some Dryopteris sp. are used as a larval food plant for moths.

Links:

USDA Plants Database

Consortium of Pacific Northwest Herbaria

WTU Herbarium Image Collection, Plants of Washington, Burke Museum

E-Flora BC, Electronic Atlas of the Flora of British Columbia

Jepson Eflora, University of California

Calphotos

Ladybird Johnson Wildflower Center

USDA Forest Service-Fire Effects Information System

Plants for a Future Database

Native American Ethnobotany, University of Michigan, Dearborn

 

Other Wood Ferns:

Coastal Wood Fern, Dryopteris arguta, is more common in California and western Oregon but can be found in a few locales northwards to areas surrounding Vancouver, B.C.  It is also known as Marginal Wood Fern, or Western Shield Fern.  Arguta means sharp-toothed.  Coastal Wood Fern grows in moist forest edges, rocky sea cliffs and drier oak woodlands.  It has scale-like chaff on its leaf stalk and evergreen glandular leaves.  Fronds are feather-shaped, 20-60 cm. long, 1-pinnate; deeply cut pinnae have small, tiny teeth along their margins.

Spinulose Wood Fern, Dryopteris carthusiana, is widespread across temperate and arctic regions in the northern hemisphere.  It is also known as Toothed Wood Fern, Narrow Buckler Fern or Shield Fern.  Spinulose means having small spines; carthusiana means from the Chartreuse Mountains in the French Alps.  Deciduous, 20-70 cm long, fronds are narrow and 2-3 pinnate, with the lowermost pinnae about the same length as adjacent pinnae.  It is preferred moose forage.

Male Fern, Dryopteris felix-mas, is common throughout much of the northern hemisphere.  It is found throughout northeastern and western North America, only spottily in the Pacific Northwest.  Felix-mas means fruitful or happy male.  Deciduous, sometimes evergreen, non-glandular fronds are broadly lance-shaped, 20-120 cm long, and 1-2 pinnate.  This very popular garden ornamental grows vase-like and withstands some drought in shade.  Some cultivated varieties are available.  It is often used for cut flower arrangements.  It is considered poisonous, but the root has been used to expel tapeworms.

 

 


 

Lady Fern, Athyrium filix-femina

Lady Fern                                                                   The Wood Fern Family–Dryopteridaceae

 Athyrium filix-femina(L.) Roth

(a-THEER-ee-um  FIH-liks–FEH-min-uh)

Names:  Athyrium possibly comes from the Greek athyros, meaning doorless, referring to the late opening of the spore cases.  Filix-femina means fern-lady, referring to its delicate fronds in comparison to the Male Fern, Dryopteris filix-mas. (Felix means happy or fruitful/fertile; a happy or fruitful lady could also be an appropriate name for this aggressive fern!)

Relationships:  There are about 180 species of Athyrium worldwide; with only two species in the mainland United States.

 

 

Distribution of Lady Fern from USDA Plants Database

Distribution: Lady Fern is abundant throughout the northern hemisphere; found in all the states and provinces in North America.

 

 

 

Habitat: It grows in moist to wet forests, meadows and streambanks. Wetland designation: FAC, Facultative, it is equally likely to occur in wetlands or non-wetlands.

Growth: Lady Fern grows to 6 feet, (2m) tall.

 

Diagnostic Characters: It has large, feathery 2-3 pinnate fronds, tapering at both ends, arising from a cluster of scaly rhizomes.  Sori, or spore cases, are elongated and curved, oblong to horseshoe-shaped.

 

 

 

 

 

 

 

 

In the Landscape: This species, with its graceful, lacy, bright, yellow-green fronds, is very eye-catching.  It may, however be a little too aggressive for a formal garden, but is ideal for a wild, moist, woodland garden, where it can freely multiply.  It dies back completely in winter.  Some may consider the withered fronds a bit unsightly.

Use by people: Natives ate the roots/rhizomes after roasting or baking in a pit.  They should always be cooked prior to consumption; many ferns contain carcinogens, so caution is advised.  A tea made from the rhizomes or stems were used for various women’s complaints and to ease pain.  The leaves were used to cover camas while baking, to cover berry baskets and to wipe fish.

Use by Wildlife: Roosevelt Elk and deer Eat Lady Fern in the fall on the Olympic Peninsula, but it is not a major food species.  Grizzly Bears also eat the fronds.

Alpine Lady Fern, Athyrium americanum is found on open, rocky slopes along streams in our mountains.  It is also known as A. distentifolium var. americanum, or A. alpestre var. americanum.  It is much smaller, with narrower, crinkled fronds.

 

Links:

USDA Plants Database

Consortium of Pacific Northwest Herbaria

WTU Herbarium Image Collection, Plants of Washington, Burke Museum

E-Flora BC, Electronic Atlas of the Flora of British Columbia

Jepson Eflora, University of California

Calphotos

Ladybird Johnson Wildflower Center

USDA Forest Service-Fire Effects Information System

Native Plants Network, Propagation Protocol Database

Plants for a Future Database

Native American Ethnobotany, University of Michigan, Dearborn

 

Western Sword Fern, Polystichum munitum

Western Sword Fern                                   The Wood Fern Family–Dryopteridaceae

 Polystichum munitum (Kaulf.) C. Presl

(Pol-ee-STIK-um  mew-NEE-tum)

Names: Polystichum means many rows, referring to the arrangement of the spore cases on the undersides of the fronds.  Munitum means armed with teeth, referring to its toothed fronds.  Western Sword Fern is also known as Sword Holly Fern, Giant Holly Fern, Christmas Fern, Pineland Sword Fern, or Chamisso’s Shield Fern.

Relationships: There are about 260 species of Polystichum worldwide with about 16 native to North America; and about 10 native to the Pacific Northwest.

 

 

Distribution of Western Sword Fern from USDA Plants Database

Distribution: Western Sword Fern is found from southeast Alaska to the central California coast, mostly on the west of the Cascades; eastward to northern Idaho into northwest Montana.  Disjunct populations have been found in South Dakota and on Guadalupe Island off Baja California.

 

 

 

 

Growth: Western Sword Fern grows up to 4.5 feet (1.5m) tall.

Habitat:  It is usually found in moist forests, but it is probably the most adaptable of all our ferns and can take a bit more sun than other ferns and some dry periods. Wetland designation: FACU, it usually occurs in non-wetlands but occasionally is found in wetlands.

Sword Fern is very common in the understory in our westside forests.

Diagnostic Characters: Large, erect fronds form from a crown of scaly rhizomes.  Fronds are once-pinnate with alternate pointed, sharp-toothed leaflets; each leaflet with a small lobe pointed forward at the base.  Sori (spore cases) are large and round arranged in two rows on the undersides of the fronds halfway between the midvein and margins.

 

 

 

 

 

 

 

In the Landscape: Western Sword Fern is the most widespread and versatile of all our native ferns.  Although at home in woodlands, it often adapts to drier, sunnier sites in landscapes.  Its tall arching fronds are most impressive planted in drifts in a woodland garden.   When grown in the sun, the fronds are dwarfed and more erect; and have pinnae (leaflets) that are crisped and crowded so that they overlap and appear overlapping.  Young ferns are also more frilly-looking.

 

Phenology: Fronds partially unroll their “fiddleheads” by late May; by late July the spores are near maturity.

Sword Fern Fiddleheads.

 

 

 

 

 

 

 

 

Use by natives:  The roots/rhizomes were generally viewed by natives as a famine food. (This plant probably should only be consumed in small quantities, if at all, due to possible presence of carcinogens or other toxins.)  The rhizomes were peeled and then boiled or baked in a pit on hot rocks covered with fronds.  The fronds were used frequently for lining baking pits and storage baskets; and were spread on drying racks to prevent berries from sticking.  They were variously used for placemats, floor coverings, bedding; and for games, dancing skirts and other decorations.  They are frequently used today in flower arrangements.

Use by wildlife:  Western Sword Fern is browsed by deer, elk, Black Bear and Mountain Beaver; frequently eaten by Roosevelt Elk on the Olympic Peninsula. The fronds may be used as nesting material for rodents.

 

Western Sword Fern outcrosses frequently and hybrids have been identified from crosses with Anderson’s Holly Fern (P. andersonii), Mountain Holly Fern, (P. scopulinum) California Sword Fern (P. californicum), Shasta Fern (P. lemmonii), and Narrowleaf Sword Fern, (P. imbricans)

Links:

USDA Plants Database

Consortium of Pacific Northwest Herbaria

WTU Herbarium Image Collection, Plants of Washington, Burke Museum

E-Flora BC, Electronic Atlas of the Flora of British Columbia

Jepson Eflora, University of California

Calphotos

Ladybird Johnson Wildflower Center

USDA Forest Service-Fire Effects Information System

Hardy Fern Library

Native Plants Network, Propagation Protocol Database

Plants for a Future Database

Native American Ethnobotany, University of Michigan, Dearborn

 

Other Polystichum sp., native to the Pacific Northwest:

Narrowleaf Sword Fern, P. imbricans is similar to Western Sword Fern and once was classified as a variety of P. munitum.  It is smaller (20-60cm) with overlapping, somewhat infolded leaflets and only scarcely scaly stipes (petioles).  It is a better choice for a sunny spot.

Anderson’s Holly Fern, P. andersonii is much rarer; found in deep woods in the mountains.  Fronds grow to 1 meter.   It has a conspicuously chaffy fiddlehead and leaf stalk.  Pinnae are deeply cut making it appear doubly pinnate.  Bulblets form at the base of pinnae near the tip and may grow into a new plant when the frond touches the ground!

Anderson’s Holly Fern

Braun’s Holly Fern, P. braunii, is big (to 1m) and has twice pinnate leaves with no basal lobes. It grows in moist woodlands.  (Native to British Columbia, southern Alaska, the Idaho panhandle—Listed as threatened or endangered in several eastern U.S. states).

California Sword Fern, P. californicum, has finely toothed leaflets rather than the prominently toothed leaflets in Western Sword Fern; each tooth is short, ending abruptly. It will grow in a variety of habitats from moist, shaded woods to open slopes, and dry, rocky terrain.  It is rare in Washington & Oregon, listed as sensitive in Washington, only found in or near the Cascades in Pierce & Thurston counties).

Kruckeberg’s Holly Fern, P. kruckebergii is believed to be a fertile hybrid of P. lonchitis & P. lemmonii. It is found sporadically in the Cascades, Sierras, & Rocky Mountains on rocks and cliffs and is considered rare or imperiled in Alaska, Montana, Idaho, California and B.C.; and “of concern” in Oregon.  Fronds are about 10-25cm long.  Short leaflets are oval to triangular, overlapping and twisted; with teeth tipped with spines.  It is named after Dr. Arthur Kruckeberg, the well-known botanist and native plant gardener and enthusiast.

Kwakiutl Holly Fern, P. kwakiutlii is known only from the type specimen, collected at Alice Arm, British Columbia in 1934. It is presumed to be one of the diploid progenitors of P. andersonii.  It also produced bulblets, but differs from P. andersonii in its completely divided pinnae (leaflets).  Kwakiutl is a name applied to the native people in British Columbia on Vancouver Island and surrounding areas.

Lemmon’s or Shasta Holly Fern, P. lemmonii: Fronds are twice pinnate; pinnae have no spines and are overlapping and twisted, making it appear cylindrical.  This species grows in serpentine rock crevices; and is found sporadically in the Cascades from B.C. to northern California.  It is only known from one site in B.C. where it is listed as threatened.

Northern Holly Fern, P. lonchitis, grows in mountains, often in rock crevices, throughout much of the northern hemisphere.  Lonchitis is from the Greek logch meaning spear, referring to its spear-shaped leaves.  It is once pinnate with spiny leaflets; resembling a miniature Sword Fern.  It is listed as endangered in New York; and is on a review list in California.

Mountain Holly Fern or Rock Sword Fern, P. scopulinum is also like a smaller Sword Fern but is shinier and more leathery with spiny-toothed leaves.  It is nearly bipinnate with long hairs on the teeth of each leaflet.  It is found in dry coniferous forest or more commonly on cliffs and talus slopes.  It is more frequent east of the Cascades and the Rocky Mountains; it also grows in eastern Canada.

Alaska Holly Fern, P. setigerum, is presumed to a hybrid between P. munitum and P. braunii.  Fronds are 2-pinnate about the middle, finely spiny-toothed.  It is found in lowland coastal forests in Alaska and B.C.  It may be able find a niche in a cool, moist woodland garden.