Comments
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Inglês
)
fornecido por eFloras
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.
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Description
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Inglês
)
fornecido por eFloras
Stems 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. Leaves monomorphic, clustered on stem, 2--40 cm; croziers sparsely villous. Petiole brown, lustrous, rounded adaxially, occasionally with prominent articulation lines near base. Blade linear-oblong to ovate-lanceolate, 1--2-pinnate proximally, 1--8 cm wide; rachis brown throughout, straight, rounded adaxially, nearly glabrous. Pinnae 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. Ultimate segments 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. Veins of ultimate segments usually obscure. Sporangia long-stalked, containing 32 or 64 spores, not intermixed with farina-producing glands.
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Pellaea glabella
(
Inglês
)
fornecido por wikipedia EN
Pellaea glabella is a fern with the common name smooth cliffbrake. It was once regarded as a reduced form or variety of Pellaea atropurpurea. P. glabella is known to exist in two cryptic species, one diploid and one tetraploid. The diploid reproduces sexually, while the tetraploid is normally apogamous. It is now known that the tetraploid form of the species is one of the parents of the original hybrid P. × atropurpurea that became the apogamous species.
Range and Habitat
P. glabella ranges widely in the United States and much of Canada, excluding the northernmost regions and Alaska. P. glabella is epipetric, normally growing on well-weathered limestone, usually in cracks with little or no soil. It can also be found on sandstone and basalt, probably in places where calcium is locally concentrated. It favors more exposed sites than P. atropurpurea.
Description
This species has sessile or nearly sessile pinnae. Sori are formed on the underside of the pinnae edges and are covered by a false indusium formed by curled under pinna edges. It can be distinguished from Pellaea atropurpurea by its smooth, not hairy, stipe and rachis (the main leaf stalk and stem).
Taxonomy
P. glabella has been assigned a total of four subspecies:
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Pellaea glabella subsp. glabella Mettenius ex Kuhn
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Pellaea glabella subsp. missouriensis (G. J. Gastony) Windham
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Pellaea glabella subsp. occidentalis (E. E. Nelson) Windham
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Pellaea glabella subsp. simplex (Butters) A. Löve & D. Löve
The subspecies glabella and simplex are the tetraploids, while missouriensis and occidentalis are the diploids. Glabella and missouriensis have hairlike scales near the midrib, while simplex and occidentalis are completely glabrous.
References
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Pellaea glabella: Brief Summary
(
Inglês
)
fornecido por wikipedia EN
Pellaea glabella is a fern with the common name smooth cliffbrake. It was once regarded as a reduced form or variety of Pellaea atropurpurea. P. glabella is known to exist in two cryptic species, one diploid and one tetraploid. The diploid reproduces sexually, while the tetraploid is normally apogamous. It is now known that the tetraploid form of the species is one of the parents of the original hybrid P. × atropurpurea that became the apogamous species.
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Pellaea glabella
(
Vietnamita
)
fornecido por wikipedia VI
Pellaea glabella Mett. ex Kuhn là một loài dương xỉ trong họ Pteridaceae. Loài này được Mett. ex Kuhn mô tả khoa học đầu tiên năm 1869.[1]
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Liên kết ngoài
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Pellaea glabella: Brief Summary
(
Vietnamita
)
fornecido por wikipedia VI
Pellaea glabella Mett. ex Kuhn là một loài dương xỉ trong họ Pteridaceae. Loài này được Mett. ex Kuhn mô tả khoa học đầu tiên năm 1869.
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