Pellaea wrightiana |
Pellaea glabella |
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Wright's cliffbrake |
pelléade glabre, simple cliff-brake, slender cliff-brake, smooth cliff-brake, smooth cliffbrake fern |
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Stems | compact, ascending, stout, 5–10 mm diam.; scales bicolored, linear-subulate, 0.1–0.3 mm wide, centers black, thick, margins brown, thin, erose-dentate. |
compact, ascending, stout, 5–10 mm diam.; scales uniformly reddish brown, linear-subulate, 0.1–0.3 mm wide, thin, margins sinuous, entire to denticulate. |
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Leaves | monomorphic, clustered on stem, 6–40 cm; croziers sparsely villous. |
monomorphic, clustered on stem, 2–40 cm; croziers sparsely villous. |
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Petiole | dark brown, lustrous, flattened or slightly grooved adaxially, without prominent articulation lines. |
brown, lustrous, rounded adaxially, occasionally with prominent articulation lines near base. |
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Blade | linear-oblong, 2-pinnate proximally, 1.5–5 cm wide; rachis brown throughout, straight, shallowly grooved adaxially, usually glabrous. |
linear-oblong to ovate-lanceolate, 1–2-pinnate proximally, 1–8 cm wide; rachis brown throughout, straight, rounded adaxially, nearly glabrous. |
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Ultimate segments | narrowly oblong, 5–20 mm, leathery, glabrous; margins recurved on fertile segments, usually covering less than 1/2 abaxial surface, borders whitish, crenulate; apex mucronate. |
oblong-lanceolate, 5–20 mm, leathery to herbaceous, glabrous except for occasional hairlike scales abaxially near midrib; margins recurved on fertile segments, covering less than 1/2 abaxial surface, borders whitish, erose-denticulate; apex obtuse. |
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Pinnae | perpendicular to rachis or slightly ascending, not decurrent on rachis, usually with 3–9 ultimate segments; costae straight, 2–20 mm, usually shorter than ultimate segments. |
somewhat ascending, decurrent on rachis, usually with 3–7 lobes or ultimate segments; costae when present straight, 1–50 mm, often shorter than ultimate segments. |
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Veins | of ultimate segments obscure. |
of ultimate segments usually obscure. |
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Sporangia | long-stalked, containing 64 spores, intermixed with sparse farina-producing glands. |
long-stalked, containing 32 or 64 spores, not intermixed with farina-producing glands. |
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2n | = 116. |
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Pellaea wrightiana |
Pellaea glabella |
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Phenology | Sporulating summer–fall. | |||||||||||||
Habitat | Cliffs and rocky slopes, on a variety of acidic to mildly basic substrates | |||||||||||||
Elevation | 300–2900 m (1000–9500 ft) | |||||||||||||
Distribution |
AZ; CO; NC; NM; OK; TX; UT; n Mexico
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AR; AZ; CO; CT; IA; ID; IL; IN; KS; KY; MA; MD; MI; MN; MO; MT; ND; NE; NM; NY; OH; OK; PA; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; ON; QC; SK; only in the flora
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Discussion | W. H. Wagner Jr. (1965) suggested that Pellaea wrightiana was a fertile allotetraploid hybrid between P. truncata (as P. longimucronata) and P. ternifolia. This hypothesis has been confirmed by isozyme analyses (M. D. Windham 1988). Pellaea wrightiana is therefore treated as a distinct species rather than a variety of P. ternifolia. This tetraploid species hybridizes with P. truncata and P. ternifolia subsp. arizonica to produce sterile triploids and tetraploids with intermediate morphology and malformed spores. Pellaea wrightiana has also hybridized with P. atropurpurea to form a rare apogamous pentaploid known only from western Oklahoma. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Pellaea glabella includes four geographically and genetically isolated taxa treated here as subspecies. D. B. Lellinger (1985) recognized three species in this difficult group, but isozyme analyses (G. J. Gastony 1988) showed that one of these (P. suksdorfiana) is an autotetraploid derivative of the diploid known as P. occidentalis. As a result, Gastony recognized just two species: P. glabella (with two varieties) and P. occidentalis (with two subspecies). The few morphologic features that distinguish these taxa, however, are subtle and environmentally plastic, and the isozyme data indicate that they are less divergent genetically than any other pair of Pellaea species in North America. Therefore, a more conservative taxonomic treatment seems warranted. Subspecies 4. (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 | Pteridaceae > Pellaea | Pteridaceae > Pellaea | ||||||||||||
Sibling taxa | ||||||||||||||
Subordinate taxa | ||||||||||||||
Synonyms | P. ternifolia var. wrightiana | |||||||||||||
Name authority | Hooker: Sp. Fil. 2: 142. (1858) | Mettenius ex Kuhn: Linnaea 36: 87. (1869) | ||||||||||||
Web links |
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