Woodsia ilvensis
Woodsia scopulina
oblong woodsia, rusty cliff fern, rusty woodsia, woodsie de l'île d'elbe
cliff-fern, mountain cliff fern, Rocky Mountain woodsia, woodsia, woodsie des rochers
compact, erect to ascending, with abundant persistent petiole bases of ± equal length;
scales uniformly brown, lanceolate.
compact, erect to ascending, with few to many persistent petiole bases of unequal lengths;
scales uniformly brown or bicolored with dark central stripe and pale brown margins, ovate to narrowly lanceolate.
4.5–25 × 1.2–3.5 cm.
9–35 × 1–8 cm.
usually brown or dark purple when mature, articulate above base at swollen node, relatively brittle and easily shattered.
usually reddish brown to dark purple proximally when mature, not articulate above base, relatively brittle and easily shattered.
narrowly lanceolate, usually 2-pinnate proximally, lacking glands, never viscid;
rachis usually with abundant hairs and scales.
lanceolate to linear-lanceolate, 2-pinnate proximally, moderately glandular, rarely somewhat viscid;
most glandular hairs with thick stalks and distinctly bulbous tips;
rachis usually with abundant glandular and nonglandular hairs.
ovate-lanceolate to deltate, longer than wide, abruptly tapered to a rounded or broadly acute apex;
largest pinnae with 4–9 pairs of pinnules;
abaxial surface with mixture of hairs and linear-lanceolate scales, adaxial surface with multicellular hairs concentrated along midrib.
lanceolate-deltate to ovate, longer than wide, abruptly tapered to a rounded or broadly acute apex, occasionally attenuate;
largest pinnae with 5–14 pairs of pinnules;
abaxial and adaxial surfaces glandular and sparsely villous, with flattened, multicellular hairs concentrated along midribs.
of narrow, hairlike segments, these uniseriate throughout, composed of cells many times longer than wide, usually surpassing mature sporangia.
of filamentous or nonfilamentous segments, these multiseriate proximally, often uniseriate distally, composed of ± isodiametric cells, concealed by or slightly surpassing mature sporangia.
averaging 39–46 µm. 2n = 82.
averaging 39–57 µm.
entire or crenate, rarely shallowly lobed;
margins nonlustrous, thin, ciliate with multicellular hairs, lacking translucent projections.
dentate, often shallowly lobed;
margins nonlustrous, thin, slightly glandular and occasionally ciliate with isolated, multicellular hairs, lacking translucent projections.
tips frequently enlarged to form whitish hydathodes visible adaxially.
tips slightly (if at all) enlarged, barely visible adaxially.
Woodsia ilvensis
Woodsia scopulina
Although generally separable by the characters given in the key, shade forms of Woodsia ilvensis with a reduced number of scales and hairs are occasionally misidentified as W. alpina. The morphologic distinctions between these species are further blurred by natural hybridization, which produces the intermediate triploid known as W. × gracilis. Some of the best characters for distinguishing these taxa are spore size and morphology. Spores average less than 46 µm in W. ilvensis, more than 46 µm in W. alpina, and are malformed and abortive in W. × gracilis. Woodsia ilvensis also hybridizes with W. oregana subsp. cathcartiana to form the sterile triploid W. × abbeae (F. S. Wagner 1987).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Woodsia scopulina shows substantial variation in leaf size, shape, and dissection, and in the abundance of multicellular hairs on the pinnae. Although much of this variation seems to be environmentally induced, recent studies (M. D. Windham 1993) have identified three chromosomal/morphologic variants that are treated here as subspecies. Diploid populations of W. scopulina are divisible into two groups, one of which (subsp. scopulina) is scattered throughout the mountainous regions of western North America while the other (subsp. appalachiana) is confined to montane habitats in the southeastern United States. These taxa seem amply distinct (T. M. C. Taylor 1947) and might be considered separate species if not for the existence of populations in the Great Lakes region and western cordillera that tend to bridge the morphologic and geographic gap between them. These intermediate populations (subsp. laurentiana) appear to be uniformly tetraploid and may have arisen through ancient hybridization between subsp. scopulina and subsp. appalachiana. In regions where subsp. laurentiana is sympatric with subsp. scopulina, the two taxa are rarely found growing together, suggesting that they differ in their ecological tolerances and/or habitat requirements.
Subspecies 3.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Scales of stems and petiole bases narrowly lanceolate, mostly bicolored with broad, usually continuous, dark central stripe; longest hairs on pinnae composed of 5-8 cells; indusial segments broad, not at all filamentous. | subsp. appalachiana |
1. Scales of stem and petiole bases ovate-lanceolate, mostly concolored or weakly bicolored with narrow, often discontinuous, dark central stripe; longest hairs on pinnae composed of 2-5 cells; indusial segments narrow, often filamentous distally. | → 2 |
2. Spores averaging 42-50 µm; stem and petiole base scales usually concolored or with a few isolated, dark, occluded cells. | subsp. scopulina |
2. Spores averaging 50-57 µm; at least some stem and petiole base scales with clusters of dark, occluded cells near center forming narrow, usually discontinuous stripe. | subsp. laurentiana |
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