Woodsia oregana
Canad. Naturalist & Quart. J. Sci. n. s. 2: 90. 1865.
Stems 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. Leaves 4–25 × 1–4 cm. Petiole reddish-brown to dark purple proximally when mature, not articulate above base, somewhat pliable and resistant to shattering. Blade 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. Pinnae 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. Pinnules dentate, often shallowly lobed; margins nonlustrous, thin, with occasional glands, lacking cilia, rarely with 1–2-celled translucent projections. Vein tips slightly (if at all) enlarged, barely visible adaxially. Indusia of narrow, usually filamentous segments, these uniseriate for most of length, composed of ± isodiametric cells, concealed by or slightly surpassing mature sporangia. Spores averaging 39–50 µm.
Distribution
Alta., B.C., Man., Ont., Que., Sask., Ariz., Calif., Colo., Idaho, Iowa, Kans., Mich., Minn., Mont., N.Dak., N.Mex., N.Y., Nebr., Nev., Okla., Oreg., S.Dak., Utah, Wash., Wis., Wyo., only in the flora
Discussion
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.
Selected References
None.
Key
| 1 | Spores averaging 39-45 µm; cells on pinnule margins regular in shape, margins appearing entire; adaxial epidermal cells averaging less than 120 µm. | Woodsia oregana subsp. oregana |
| 1 | Spores averaging 45-50 µm; cells on pinnule margins irregular in shape, margins usually minutely dentate and appearing ragged; adaxial epidermal cells averaging more than 120 µm. | Woodsia oregana subsp. cathcartiana |
"/5lengthofblade" is not declared as a valid unit of measurement for this property."thin" is not a number.