Polypodium hesperium
Polypodium scouleri
western polypody, western polypody fern
coast, coast polypody, leather fern, leather-leaf fern, leather-leaf polypody, leathery polypody, leathery polypody fern, Scouler's polypody
occasionally whitish pruinose, slender to moderately stout, to 6 mm diam., acrid- to sweet-tasting: scales concolored, brown or slightly mottled, often darker near point of attachment, lanceolate, usually symmetric, margins entire to denticulate.
conspicuously whitish pruinose, stout, 3–12 mm diam., bland to slightly sweet-tasting;
scales concolored to weakly bicolored, uniformly dark brown or with pale margins and base, lanceolate, symmetric, margins denticulate.
to 35 cm.
to 85 cm.
slender, to 1.5 mm diam.
stout, to 3 mm diam.
oblong to lanceolate-ovate, occasionally deltate, pinnatifid, usually widest at or near middle, to 7 cm wide, herbaceous to somewhat leathery;
rachis sparsely scaly to glabrescent abaxially, glabrous adaxially;
scales linear-lanceolate, usually less than 6 cells wide.
ovate-lanceolate, pinnatifid, usually widest just above base, to 27 cm wide, stiff and leathery;
rachis sparsely scaly to glabrescent abaxially, glabrous adaxially;
scales bicolored, ovate-lanceolate, much more than 6 cells wide.
oblong to linear-lanceolate, less than 12 mm wide;
margins entire to crenulate or obscurely serrate;
apex obtuse to acute;
midrib glabrous adaxially.
oblong to linear, usually more than 12 mm wide;
margins entire to crenulate;
apex rounded to rarely broadly acute;
midrib glabrous adaxially.
midway between margin and midrib, less than 3 mm diam., oval when immature.
crowded against midrib, usually more than 3 mm diam., circular when immature.
more than 58 µm, rugose to verrucose or tuberculate, surface projections commonly less than 3 µm.
usually less than 52 µm, rugose, surface projections less than 3 µm tall.
free.
anastomosing, usually forming 1 row of areoles.
absent.
absent.
= 148.
= 74, 111.
Polypodium hesperium
Polypodium scouleri
Using morphologic and chromosomal data, F. A. Lang (1971) proposed that Polypodium hesperium originated through allotetraploidy involving P. glycyrrhiza and P. amorphum, a hypothesis recently supported by electrophoretic studies (C. H. Haufler, M. D. Windham, and E. W. Rabe, unpublished). Variations in spore surface morphology and banding patterns observed in isozyme studies indicate that P. hesperium may have originated more than once from different individuals of the same species. Some collections of P. hesperium can be mistaken for P. glycyrrhiza, but the latter species is easily distinguished by its pubescent rachises, linear blade scales, and smaller spores (less than 58 µm). Although P. amorphum has sporangiasters and P. hesperium lacks them, misshapen sporangia in P. hesperium can mimic these distinctive soral structures. Therefore, it is often necessary to use a combination of soral, stem scale, and blade scale features (discussed in the key) to separate P. hesperium from P. amorphum. Hybridization occurs between P. hesperium and each of its progenitor diploids to form triploid individuals with misshapen spores (F. A. Lang 1971). Rare, sterile, tetraploid hybrids with P. saximontanum have also been detected (M. D. Windham, unpublished).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
The distinctive Polypodium scouleri has occasionally been assigned to the genus Goniophlebium because of its anastomosing venation and conspicuous areoles. Its venation pattern can be quite variable, however, and cannot be used as the sole feature distinguishing P. scouleri from P. californicum. Combining venation characteristics with others provided in the key distinguishes it clearly from its congeners in Polypodium. Some evidence suggests that P. scouleri hybridizes with P. californicum (S. A. Whitmore, unpubl.). I. Manton (1951) reported diploid and triploid cytotypes for P. scouleri, and variation in spore size suggests that the species may also include tetraploid populations.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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- Local floras: BC, CA, OR, WA
- Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria
- WildflowerSearch
- iNaturalist (observations)
- USDA Plants Database
- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
