Woodsia ilvensis |
Woodsia oregana |
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oblong woodsia, rusty cliff fern, rusty woodsia, woodsie de l'île d'elbe |
cliff fern, Oregon cliff-fern, Oregon woodsia, western cliff fern, woodsie de l'Oregon |
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Stems | 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 often uniformly brown but at least some bicolored with dark central stripe and pale brown margins, narrowly lanceolate. |
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Leaves | 4.5–25 × 1.2–3.5 cm. |
4–25 × 1–4 cm. |
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Petiole | usually brown or dark purple when mature, articulate above base at swollen node, relatively brittle and easily shattered. |
reddish brown to dark purple proximally when mature, not articulate above base, somewhat pliable and resistant to shattering. |
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Blade | narrowly lanceolate, usually 2-pinnate proximally, lacking glands, never viscid; rachis usually with abundant hairs and scales. |
linear-lanceolate to narrowly ovate, pinnate-pinnatifid or 2-pinnate proximally, sparsely to moderately glandular, never viscid; glandular hairs with thin stalks and slightly expanded tips; rachis with scattered glandular hairs and occasional hairlike scales. |
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Pinnae | 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. |
ovate-deltate to elliptic, longer than wide, abruptly tapered to a rounded or broadly acute apex; largest pinnae with 3–9 pairs of pinnules; abaxial and adaxial surfaces glabrescent to moderately glandular, lacking nonglandular hairs or scales. |
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Indusia | of narrow, hairlike segments, these uniseriate throughout, composed of cells many times longer than wide, usually surpassing mature sporangia. |
of narrow, usually filamentous segments, these uniseriate for most of length, composed of ± isodiametric cells, concealed by or slightly surpassing mature sporangia. |
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Spores | averaging 39–46 µm. 2n = 82. |
averaging 39–50 µm. |
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Pinnules | entire or crenate, rarely shallowly lobed; margins nonlustrous, thin, ciliate with multicellular hairs, lacking translucent projections. |
dentate, often shallowly lobed; margins nonlustrous, thin, with occasional glands, lacking cilia, rarely with 1–2-celled translucent projections. |
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Vein | tips frequently enlarged to form whitish hydathodes visible adaxially. |
tips slightly (if at all) enlarged, barely visible adaxially. |
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Woodsia ilvensis |
Woodsia oregana |
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Phenology | Sporulating summer–early fall. | |||||
Habitat | Cliffs and rocky slopes, found on variety of substrates including serpentine | |||||
Elevation | 0–1500 m (0–4900 ft) | |||||
Distribution |
AK; CT; IA; IL; MA; MD; ME; MI; MN; NC; NH; NJ; NY; OH; PA; RI; VA; VT; WI; WV; AB; BC; MB; NB; NF; NS; NT; ON; QC; SK; YT; Greenland; n Eurasia
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AZ; CA; CO; IA; ID; KS; MI; MN; MT; ND; NE; NM; NV; NY; OK; OR; SD; UT; WA; WI; WY; AB; BC; MB; ON; QC; SK; only in the flora
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Discussion | 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.) |
The variability and promiscuity of Woodsia oregana have been major sources of taxonomic difficulties in Woodsia, and more work will be necessary before relationships in this complex are fully resolved. As defined here, W. oregana comprises two subspecies that are chromosomally and biochemically distinct. In addition, the two taxa are nearly allopatric, with the diploid (subsp. oregana) confined to the Pacific Northwest and the tetraploid (subsp. cathcartiana) extending from the southwestern United States to eastern Canada. Isozyme studies indicate that subsp. cathcartiana is not an autotetraploid derived from known diploid populations of subsp. oregana, as was hypothesized by D. F. M. Brown (1964), and it may be more appropriate to recognize these taxa as distinct species. The morphologic features that distinguish these subspecies are very subtle, however, and they are associated primarily with differences in chromosome number. Until further systematic analyses are undertaken, these cytotypes should be maintained as subspecies of W. oregana. Subspecies 2. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 2. | FNA vol. 2. | ||||
Parent taxa | Dryopteridaceae > Woodsia | Dryopteridaceae > Woodsia | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Acrostichum ilvense | |||||
Name authority | (Linnaeus) R. Brown: Trans. Linn. Soc. London, Bot. 11: 173. (1813) | D. C. Eaton: Canad. Naturalist & Quart. J. Sci. n. s. 2: 90. (1865) | ||||
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