Pellaea ternifolia |
Pellaea bridgesii |
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trans-Pecos cliffbrake |
Bridges' cliff-brake |
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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 mostly weakly bicolored, linear-subulate, 0.1–0.3 mm wide, centers dark brown, thin, margins lighter, thin, denticulate to entire. |
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Leaves | monomorphic, clustered on stem, 10–50 cm; croziers sparsely to densely villous. |
monomorphic, clustered on stem, 7–30 cm; croziers nearly glabrous. |
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Petiole | black or dark purple, lustrous, rounded or slightly flattened adaxially, without prominent articulation lines. |
dark brown, lustrous, rounded adaxially, without prominent articulation lines. |
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Blade | linear to ovate, deeply pinnate-pinnatifid proximally, 2.5–8 cm wide; rachis black or purple throughout, straight, often flattened adaxially, glabrous or villous. |
linear, 1-pinnate, 1.5–4 cm wide; rachis brown throughout, straight, rounded adaxially, glabrous. |
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Ultimate segments | linear-oblong, 10–40 mm, leathery, glabrous to sparsely villous abaxially on midrib; margins recurved on fertile segments, rarely covering more than 1/2 abaxial surface, borders whitish, entire; apex mucronate. |
broadly ovate to elliptic, 7–20 mm, leathery, glabrous; margins plane, not recurved, not covering abaxial surface, borders whitish, entire; apex obtuse to rounded. |
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Pinnae | perpendicular to rachis or slightly ascending, not decurrent on rachis, ternate at base of leaf; costae absent. |
perpendicular to slightly ascending, usually not decurrent on rachis, simple and unlobed; costae absent. |
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Veins | of ultimate segments obscure. |
of ultimate segments obscure. |
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Sporangia | long-stalked, containing 64 spores, not intermixed with farina-producing glands. |
sessile or subsessile, containing 64 spores, intermixed with abundant farina-producing glands. |
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2n | = 58. |
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Pellaea ternifolia |
Pellaea bridgesii |
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Phenology | Sporulating summer–fall. | |||||||||
Habitat | Rocky slopes and cliffs, on granitic substrates | |||||||||
Elevation | 1200–3600 m (3900–11800 ft) | |||||||||
Distribution |
AZ; TX; Mexico; Central America; South America; Pacific Islands in Hawaii
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CA; ID; NV; OR
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Discussion | Subspecies 3 (3 in the flora). Pellaea ternifolia is represented in the flora by three morphologically and chromosomally distinct taxa. These discrete genetic entities also show a tendency toward geographic isolation and are treated here as subspecies. Diploid populations referred to P. ternifolia subsp. ternifolia are scattered from Texas through Mexico to South America. The pubescent tetraploid (P. ternifolia subsp. villosa) follows the Sierra Madre Oriental from Puebla, Mexico, north to Texas; the glabrous tetraploid (P. ternifolia subsp. arizonica) occurs in Arizona, Texas, and northern Mexico. Isozyme and chromosome studies suggest that both tetraploids are segmental allopolyploids produced by hybridization between subsp. ternifolia and other (as yet unidentified) diploid elements within P. ternifolia. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
The morphology of Pellaea bridgesii is so distinctive that its sectional (and even generic) placement in Pellaea has long been a source of contention. W. H. Wagner Jr. et al. (1983) documented the existence of sterile diploid hybrids (called P. × glaciogena) between P. bridgesii and P. mucronata (see reticulogram), suggesting that P. bridgesii is most closely related to members of sect. Pellaea. In addition to the more obvious characters mentioned above, P. bridgesii is distinguished from other North American species (except P. ternifolia) by its anastomosing veins. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 2, p. 180. | FNA vol. 2. | ||||||||
Parent taxa | Pteridaceae > Pellaea | Pteridaceae > Pellaea | ||||||||
Sibling taxa | ||||||||||
Subordinate taxa | ||||||||||
Synonyms | Pteris ternifolia | |||||||||
Name authority | (Cavanilles) Link: Fil. Spec. 59. (1841) | Hooker: Sp. Fil. 2: 238, plate 142b. (1858) | ||||||||
Web links |