Comments
provided by eFloras
Polypodium appalachianum is a newly recognized species traditionally identified as the diploid cytotype of P . virginianum (A. M. Evans 1971; I. Manton and M. Shivas 1953). Because the tetraploid cytotype is an allopolyploid (C. H. Haufler and Wang Z. R. 1991), and the type specimen of P . virginianum is tetraploid (R. Cranfill and D. M. Britton 1983), the diploid is recognized here as a distinct species, P . appalachianum . Some collections of P . appalachianum can be difficult to distinguish from P . virginianum , but the latter species has spores averaging more than 52 µm, and P . appalachianum has spores less than 52 µm. Frequent hybridization between P . appalachianum and P . virginianum forms morphologically intermediate, triploid individuals with misshapen spores. Particularly confusing is the frequent occurrence of the triploid sympatric with only one parent or with neither parent nearby.
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Description
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Stems often whitish pruinose, slender, to 6 mm diam., acrid-tasting; scales concolored to weakly bicolored, uniformly golden brown or slightly darker near apex, lanceolate, contorted distally, margins denticulate. Leaves to 40 cm. Petiole slender, ± 1.5 mm diam. Blade elongate-deltate, rarely oblong, pinnatifid, usually widest at or near base, to 9 cm wide, herbaceous to somewhat leathery; rachis sparsely scaly to glabrescent abaxially, glabrous adaxially; scales lanceolate-ovate, usually more than 6 cells wide. Segments linear to oblong, less than 8 mm wide, margins entire to crenulate; apex acute to narrowly rounded; midrib glabrous adaxially. Venation free. Sori midway between margin and midrib to nearly marginal, less than 3 mm diam., circular when immature. Sporangiasters present, usually more than 40 per sorus, heads densely covered with glandular hairs. Spores less than 52 µm, verrucose, projections less than 3 µm tall. 2 n = 74.
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Distribution
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N.B., Nfld., N.S., Ont., P.E.I., Que.; Ala., Conn., Del., D.C., Ga., Ky., Maine, Md., Mass., N.H., N.J., N.Y., N.C., Ohio, Pa., R.I., S.C., Tenn., Vt., Va., W.Va.
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Habitat
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Sporulating summer--fall. Cliffs and rocky slopes; on a variety of substrates; 0--1800m.
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Polypodium appalachianum
provided by wikipedia EN
Polypodium appalachianum is a fern species native to eastern North America. Sometimes called the Appalachian polypody[1] or Appalachian rockcap fern, it is very similar in appearance to Polypodium virginianum. For years, P. virginianum—long considered a variety of the British Polypodium vulgare—was recognized as having cryptic races, with diploid, triploid, and tetraploid representatives. Since the triploid specimens bore abortive spores, it was apparently the hybrid between the diploid and tetraploid groups. In 1991, it was resolved that the type of P. virginianum was the tetraploid series, and that it is an allotetraploid species of hybrid origin, with the diploid species as one parent. The diploid species was then named P. appalachianum. The other parent of P. virginianum was found to be Polypodium sibiricum. The tetraploid of hybrid derivation tolerates warmer climates than either parent.
Polypodium sibiricum is also now known to be one of the parents of the allotetraploid Polypodium vulgare, along with Polypodium glycyrrhiza.[2]
P. appalachianum is an epipetric plant, preferring sandstone or other hard, noncalcareous rocks. However, it is known to grow as an epiphyte in the Smoky Mountains. Throughout much of its range, it will be found to grow in places more sheltered from the sun and heat than is P. virginianum. Both species, and their hybrid, can form large clonal colonies, forming dense mats that hold organic matter in place on rock shelves and surfaces.
References
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^ USDA, NRCS (n.d.). "Polypodium appalachianum". The PLANTS Database (plants.usda.gov). Greensboro, North Carolina: National Plant Data Team. Retrieved 12 October 2015.
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^ Haufler, Christopher H.; Windham, Michael D.; Rabe, Eric W. (1995). "Reticulate Evolution in the Polypodium vulgare Complex". Systematic Botany. 20 (2): 89–109. doi:10.2307/2419442. JSTOR 2419442.
- USDA Plants Profile of Polypodium appalachianum: [1]
- Flora of North America entry for Polypodium appalachianum: [2]
- Species citation: American Fern Journal volume 81, number 1, page 18, 1991. JStor reference: [3]
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Polypodium appalachianum as epiphyte in the Smoky Mountains: American Fern Journal volume 93, number 1, pages 36–41, 2003. JStor reference: [4]
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Polypodium appalachianum: Brief Summary
provided by wikipedia EN
Polypodium appalachianum is a fern species native to eastern North America. Sometimes called the Appalachian polypody or Appalachian rockcap fern, it is very similar in appearance to Polypodium virginianum. For years, P. virginianum—long considered a variety of the British Polypodium vulgare—was recognized as having cryptic races, with diploid, triploid, and tetraploid representatives. Since the triploid specimens bore abortive spores, it was apparently the hybrid between the diploid and tetraploid groups. In 1991, it was resolved that the type of P. virginianum was the tetraploid series, and that it is an allotetraploid species of hybrid origin, with the diploid species as one parent. The diploid species was then named P. appalachianum. The other parent of P. virginianum was found to be Polypodium sibiricum. The tetraploid of hybrid derivation tolerates warmer climates than either parent.
Polypodium sibiricum is also now known to be one of the parents of the allotetraploid Polypodium vulgare, along with Polypodium glycyrrhiza.
P. appalachianum is an epipetric plant, preferring sandstone or other hard, noncalcareous rocks. However, it is known to grow as an epiphyte in the Smoky Mountains. Throughout much of its range, it will be found to grow in places more sheltered from the sun and heat than is P. virginianum. Both species, and their hybrid, can form large clonal colonies, forming dense mats that hold organic matter in place on rock shelves and surfaces.
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