BC Conservation Data Centre: Species Summary
Dryopteris arguta
coastal wood fern
| Scientific Name: | Dryopteris arguta (Kaulfuss) Watt | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| English Name: | coastal wood fern | ||||||||||
| Classification / Taxonomy | |||||||||||
| Scientific Name - Concept Reference: | Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR. | ||||||||||
| Classification Level: | Species | ||||||||||
| Species Group: | Vascular Plant | ||||||||||
| Species Code: | DRYOARG | ||||||||||
|
|||||||||||
| Conservation Status / Legal Designation | |||||||||||
| Global Status: | G5 (Nov 2011) | ||||||||||
| Provincial Status: | S3 (Apr 2019) | ||||||||||
| BC List: | Blue | ||||||||||
| Provincial FRPA list: | |||||||||||
| Provincial Wildlife Act: | |||||||||||
| COSEWIC Status: | Special Concern (May 2021) | ||||||||||
| SARA Schedule: | 1 - Special Concern (Jun 2003) | ||||||||||
| General Status Canada: | 3 - Sensitive (2010) | ||||||||||
| Ecology & Life History | |||||||||||
| General Description: | |||||||||||
| Technical Description: | |||||||||||
| Subspecies Comments: | There are no recognized subspecies of Dryopteris arguta in B.C. | ||||||||||
| Identification Comments: | Dryopteris arguta is an evergreen, tufted fern that arises from a stout, short-creeping rhizome and measures up to 70 cm tall. Fronds are leathery, bipinnate (or pinnate pinnatifid) and arise from a stout leaf stalk (half the length of frond). Pinnules are oblong and twice serrated with long spreading spine-like teeth. Lance shaped, bright, chestnut coloured scales are abundant on rhizomes, stems, and the undersides of pinnae. Dark brown to black sori are distributed on the underside of pinnules midway between the midvein and leaf margin; indusia are yellowish, kidney shaped, and lack glands (Jamison and Douglas 1998; Douglas et al. 2000). | ||||||||||
| Similar Species: | Dryopteris arguta may be confused with Dryopteris filix-mas, which is a similar species but lacks the long spreading spine-like teeth on pinnules and the lance shaped, chestnut coloured scales on the undersides of pinnae of D. arguta. Scales on pinnae of D. filix-mas are linear or hair-like (Jamison and Douglas 1998). | ||||||||||
| Provincial Reproduction Comments: | Dryopteris arguta can reproduce vegetatively through rhizome growth and can form large colonies (Jamison and Douglas 1998). It is not known if new colonies are being formed from spore dispersal events. Spores are wind dispersed and can travel thousands of kilometres on winds and in high altitude jet streams. The scattered distribution of D. arguta in south-coastal B.C. and its approximately 200-km distance from U.S. populations suggest that some long distance dispersal occurs, but it is not known how frequently. On the other hand, if populations of D. arguta are relicts of a once broader distribution, then the rate of dispersal may be very low. Jamison and Douglas (1998) suggested that the dry, rapidly drained soils where B.C. populations of D. arguta occur are not ideal for spore germination, gamete development, or gamete fusion, and that rhizome elongation is likely the principal mode of reproduction. Jamison and Douglas (1998) proposed that the predominance of vegetative propagation could also be explained by the species being stressed at the northern edge of its range. It is not known whether sexual reproduction is occurring. No gametophytes were located at the sites in 1996 (Jamison and Douglas 1998), but sampling took place in late summer, not during the wet spring season. It is also not known whether Dryopteris arguta is predominantly outcrossing or self-fertile; outcrossing occurs in heavy rainfalls when gametes are flushed away from one gametophyte towards another (Jamison and Douglas 1998). The predominance of vegetative spread or self-fertilization of gametes can result in low genetic variability within populations. It is, therefore, important to determine the level of self-fertilization and the ratio of sexual vs. asexual reproduction for this species. | ||||||||||
| Provincial Ecology Comments: | The autecology of Dryopteris arguta has not been well studied, particularly in B.C. Specific factors affecting population survival, population age structure, recruitment rate, seedling survival rates, mortality rates, and growth rates are not known. Year-to-year fluctuations in patterns of survival, growth, and reproduction have also not been well studied. Jamison and Douglas (1998) noted that robust populations with many young plants were more commonly found in coastal wooded slope habitats. The authors inferred that these habitats provide optimal light, soil, and moisture conditions for D. arguta growth. In contrast, on rock outcrops and cliffs with little mineral soil and greater exposure to sun, wind, and storms, D. arguta appears to be crowded and stressed (Jamison and Douglas 1998). D. arguta reaches maturity in one to five years, and each fertile frond can produce 13.5-15 million spores (Jamison and Douglas 1998). Spores are wind dispersed and can travel thousands of kilometres on winds and in high altitude jet streams. D. arguta is also capable of spreading vegetatively via underground rhizome elongation and can form large colonies (Jamison and Douglas 1998). The influence of invasive species, competitors, diseases, and insect pests on D. arguta was not discussed in Jamison and Douglas (1998). | ||||||||||
| Habitats: (Type / Subtype / Dependence) |
Forest / Conifer Forest - Dry / Facultative - frequent use
Forest / Deciduous/Broadleaf Forest / Facultative - occasional use Forest / Garry Oak Woodland / Facultative - frequent use Forest / Mixed Forest (deciduous/coniferous mix) / Facultative - frequent use Rock/Sparsely Vegetated Rock / Cliff / Facultative - frequent use Rock/Sparsely Vegetated Rock / Garry Oak Coastal Bluffs / Facultative - frequent use Rock/Sparsely Vegetated Rock / Rock/Sparsely Vegetated Rock / Facultative - frequent use |
||||||||||
| Provincial Habitat Comments: | In B.C., Dryopteris arguta occurs on coastal wooded slopes under open forest canopies of Pseudotsuga menziesii, Quercus garryana, and Arbutus menziesii, or on rocky coastal cliffs and outcrops often with stunted Q. garryana and Holodiscus discolor (Jamison and Douglas 1998). Other associated plants in the forested sites include H. discolor, Polystichum munitum, and Mahonia nervosa. In the more rocky exposed sites, Lonicera hispidula, Amelanchier alnifolia, and Arctostaphylos uva-ursi are commonly associated with Dryopteris arguta. Site exposure is typically southeastern, southwestern, or southern, and slopes are moderately steep (mostly greater than 30%) (Jamison and Douglas 1998). Soils are mostly very dry to moderately dry, rapidly drained, and nitrogen-medium (Jamison and Douglas 1998). D. arguta occurs in the drier subzone of the Coastal Douglas-fir biogeoclimatic zone (CDFmm) (Douglas et al. 2002). More specifically, D. arguta is often associated with the Garry oak ecosystems (particularly on Hornby, East Ballenas, and Gerald Islands) (Jamison and Douglas 1998). D. arguta habitats experience a cool mesothermal climate of mild, wet winters and dry, warm summers. | ||||||||||
| Provincial Phenology: (1st half of month/ 2nd half of month) |
|||||||||||
| Provincial Phenology Comments: | Little is known about the phenology of Dryopteris arguta. It is an evergreen species, a trait that Jamison and Douglas (1998) speculated is an adaptation that allows it to persist north of its main range. A large number of spores are often retained on D. arguta fronds over winter and are released in the spring (Farrar 1976 in Jamison and Douglas 1998). Spore viability averages three years or more for Dryopteris species (Jamison and Douglas 1998). Spore germination, early gametophyte development, and gamete fusion likely occur in early spring when soils are sufficiently moist, but this has not been documented for D. arguta in B.C. No gametophytes were observed at any of the known localities in 1996, but Jamison and Douglas (1998) surveyed populations between July and September, not in the wet spring season when the gametophytes would be present. The presence of sori was not documented by the authors during these surveys. Spore production and maturation generally occurs towards the end of the growing season for D. arguta and other temperate zone species (Jamison and Douglas 1998). | ||||||||||
| Elevation (m) (min / max): | Provincial: 2 / 100 | ||||||||||
| Known Pests: | |||||||||||
| Pollen Vector: | |||||||||||
| Pollinator: | |||||||||||
| Dispersal: | |||||||||||
| Provincial Inventory | |||||||||||
| Inventory Priority: | |||||||||||
| Ownership of occurrences (Known locations): | Mostly private | ||||||||||
| Inventory Need: | Further inventories that target preferred habitats of Dryopteris arguta (e.g., southwest, southeast or south-facing dry slopes or rock outcrops) on the Gulf Islands and appropriate coastlines of Vancouver Island are needed. More importantly, it is recommended that all known occurrences be re-inventoried given that it has been almost 10 years since many of them were examined. | ||||||||||
| Inventory Comments: | Extensive surveys of previously known element occurrences of Dryopteris arguta and new potential sites were completed in 1996 (Jamison and Douglas 1998). Jamison and Douglas (1998) found six new populations and suggested that additional populations may occur on inaccessible rocky cliffs and steep, dry forested slopes on the northern Gulf Islands and adjacent Vancouver Island. Nineteen northern Gulf Islands were surveyed for rare vascular plants by B.C. Conservation Data Centre (CDC) personnel and colleagues in May 1998 (J. Penny, pers. comm., 2005). They focused on islands that had not been previously visited due to poor accessibility. Only two new occurrences of D. arguta were reported during this survey. | ||||||||||
| Economic Attributes | |||||||||||
| Provincial Economic Comments: | No economic uses of Dryopteris arguta are known in B.C., but other species of Dryopteris are cultivated for use in outdoor gardens. | ||||||||||
| Distribution | |||||||||||
| Endemic: | N | ||||||||||
| Disjunct, more common elsewhere: | Y | ||||||||||
| Peripheral, major distribution elsewhere: | Y | ||||||||||
| Authors / Contributors | |||||||||||
| Global Information Author: | |||||||||||
| Last Updated: | |||||||||||
| Provincial Information Author: | Bartemucci, P. | ||||||||||
| Last Updated: | Mar 15, 2005 | ||||||||||
| Last Literature Search: | |||||||||||
| References and Related Literature | |||||||||||
B.C. Ministry of Environment. Recovery Planning in BC. B.C. Minist. Environ. Victoria, BC. |
|||||||||||
Douglas, G.W., D. Meidinger, and J. Penny. 2002. Rare Native Vascular Plants of British Columbia, 2nd ed. B.C. Conserv. Data Centre, Terrestrial Inf. Branch, Victoria. 358pp. |
|||||||||||
Douglas, G.W., D. Meidinger, and J. Pojar, eds. 2000. Illustrated Flora of British Columbia, Vol. 5, Dicotyledons (Salicaceae through Zygophyllaceae) and Pteridophytes. B.C. Minist. Environ., Lands and Parks, and B.C. Minist. For., Victoria. 389pp. |
|||||||||||
Jamison, J.A., and G.W. Douglas. 1998. Status of the Coastal Wood Fern, Dryopteris arguta (Dryopteridaceae), in Canada. Can. Field-Nat. 112(2):284-288. |
|||||||||||
Jamison, J.A., and G.W. Douglas. 1998. Status Report on Coastal Wood fern, Dryopteris arguta, in Canada. Unpubl. rep. submitted to the Comm. on the Status of Endangered Wildl. in Can. Ottawa. 23pp. |
|||||||||||
Please visit the website Conservation Status Ranks for definitions of the data fields used in this summary report.
Suggested Citation:
B.C. Conservation Data Centre. Species Summary: Dryopteris arguta. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 13, 2026).