Woodsia glabella
Woodsia ilvensis
smooth cliff fern, smooth woodsia, woodsie glabre
oblong woodsia, rusty cliff fern, rusty woodsia, woodsie de l'île d'elbe
compact, erect to ascending, with cluster of persistent petiole bases of ± equal length;
scales uniformly brown, lanceolate.
compact, erect to ascending, with abundant persistent petiole bases of ± equal length;
scales uniformly brown, lanceolate.
3.5–15 × 0.5–1.2 cm.
4.5–25 × 1.2–3.5 cm.
green or straw-colored throughout, articulate above base at swollen node, somewhat pliable and resistant to shattering.
usually brown or dark purple when mature, articulate above base at swollen node, relatively brittle and easily shattered.
linear to linear-lanceolate, pinnate-pinnatifid proximally, glabrous or with occasional sessile glands, never viscid;
rachis glabrous.
narrowly lanceolate, usually 2-pinnate proximally, lacking glands, never viscid;
rachis usually with abundant hairs and scales.
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.
of narrow hairlike segments, these uniseriate throughout, composed of cells many times longer than wide, usually surpassing mature sporangia.
of narrow, hairlike segments, these uniseriate throughout, composed of cells many times longer than wide, usually surpassing mature sporangia.
averaging 39–45 µm. 2n = 78.
averaging 39–46 µm. 2n = 82.
pinnae fan-shaped, wider than long;
distal pinnae ovate-lanceolate, longer than wide, abruptly tapered to a rounded or broadly acute apex;
largest pinnae with 1–3 pairs of pinnules, abaxial and adaxial surfaces glabrous.
entire or broadly crenate;
margins nonlustrous, thin, lacking cilia or translucent projections.
entire or crenate, rarely shallowly lobed;
margins nonlustrous, thin, ciliate with multicellular hairs, lacking translucent projections.
tips slightly (if at all) enlarged, barely visible adaxially.
tips frequently enlarged to form whitish hydathodes visible adaxially.
Woodsia glabella
Woodsia ilvensis
Woodsia glabella is a well-marked species occasionally confused with narrow, glabrescent forms of W. alpina and W. oregana subsp. oregana. These taxa are readily distinguished from W. glabella by their petioles, which are reddish brown or dark purple near the base.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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.)
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