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Polypodium appalachianum

(Appalachian Polypody)

Overview

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Interesting Facts

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Common Names

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Common Names in English:

Appalachian Polypody, Appalachian Rockcap Fern

Common Names in French:

Polypode Des Appalaches

Description

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Family Polypodiaceae

Plants perennial , terrestrial , on rock, or often epiphytic, erect , arching , or occasionally pendent. Stems long- to short-creeping, branched or not, bearing scales and few to numerous roots , usually dictyostelic. Leaves monomorphic to dimorphic , circinate in bud. Petiole usually articulate at base [rarely nonarticulate , as in Loxogramme ], lacking scales or sometimes scaly , with usually 3 vascular bundles . Blade simple to often pinnatifid , pinnatisect , or pinnate, infrequently more divided ; rachis grooved or not adaxially. Veins free (and simple to several times forked ) to often anastomosing in complex systems , areoles with or without included veinlets . Indument on blade absent, or petiole, rachis, costae, and sometimes blade tissue usually bearing hairs (these often septate and with reddish crosswalls) and/or scales. Sori borne abaxially on veins, round to oblong , occasionally elongate , rarely marginal , rarely covering surface; paraphyses present or absent; sporangia with stalk of 2 or 3 rows of cells ; indusia absent. Spores usually transparent or yellowish (rarely greenish), all 1 kind, bilateral , monolete [rarely trilete, as in some Loxogramme], surface most often smooth , tuberculate , verrucose , or granulate , occasionally spiny , 64 per sporangium (spores globose and 32 per sporangium in apogamous spp. ) . Gametophytes green, aboveground, cordate or elliptic , glabrous or sometimes glandular ; archegonia and antheridia borne on lower surface, antheridia 3-celled.

Genera ca. 40, species perhaps 500 (7 genera, 25 species in the flora ) : worldwide, especially tropics and subtropics.

Genera in this family are variously circumscribed, and the New World species historically were placed in the single genus Polypodium . Many of the segregates recognized here are still placed in Polypodium in recent floristic accounts. Limits of genera in both Old World and New World are controversial and are currently under study by several workers.[1]

Genus Polypodium

Plants on rock, occasionally terrestrial or epiphytic. Stems creeping , usually branched, 3--15 mm diam., sometimes whitish pruinose ; scales concolored to bicolored , lanceolate to ovate-acuminate, not clathrate to strongly clathrate, glabrous , margins entire to denticulate . Leaves monomorphic , closely spaced to distant , not conspicuously narrowed at tip , to 90 cm. Petiole articulate to stem, straw-colored, somewhat flattened or grooved to nearly terete , winged distally. Blade broadly ovate to deltate, pinnatifid to 1-pinnate at base , not pectinate , usually with fewer than 25 pairs of pinnae, not glaucous or conspicuously scaly ; rachis sparsely scaly to glabrescent abaxially, puberulent to glabrous adaxially; scales ovate-lanceolate to linear , not peltate or clathrate. Segments linear to oblong ; margins entire to serrate; apex rounded to attenuate. Venation free to anastomosing, if strongly anastomosing, then never with more than 1 included veinlet in fertile areoles. Sori often confined to distal region of leaf, discrete, circular to oval when immature , borne at tips of single veins, in 1--3 rows on either side of midrib ; indument absent or of modified sporangia (sporangiasters), often bearing glandular hairs on bulbous head . Spores monolete, rugose to tuberculate . x = 37.

Species ca. 100: worldwide.

Some species traditionally included in Polypodium are treated here in other genera, for example, Pleopeltis and Pecluma.

Except for the tropical species Polypodium triseriale, North American Polypodium is a complex assemblage of interactive species. The North American species have ties to European taxa (e.g. , P . vulgare sensu stricto , which probably originated by allopolyploidy between P . glycyrrhiza and P . sibiricum ) but are quite distinct from them. Morphologic comparisons and continuing biochemical and molecular studies indicate that two groups of diploid species occur within the North American P . vulgare complex. One group includes P . glycyrrhiza and P . californicum ; the second, P . amorphum, P . appalachianum, and P . sibiricum . Allopolyploid species have originated following hybridizations within a species group (i.e. , P . calirhiza from P . glycyrrhiza × californicum, P . saximontanum from P . amorphum × sibiricum, and P . virginianum from P . appalachianum × sibiricum ) as well as between members of the two groups (i.e., P . hesperium from P . amorphum × glycyrrhiza ) . These reticulate relationships are summarized in the reticulogram. We consider P . scouleri to be peripheral to the "core" diploids even though hybrids have been reported.[2]

Physical Description

Species Polypodium appalachianum

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. Sporulating summer--fall. [source]

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. [source]

Habit: Forb/herb

Habitat

Cliffs and rocky slopes ; on a variety of substrates; 0--1800 m (Ref. 102941).

Biology

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Reproduction

Duration: Perennial

Taxonomy

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Similar Species

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Members of the genus Polypodium

ZipcodeZoo has pages for 37 species, subspecies, varieties, forms, and cultivars in this genus:

P. amorphum (Irregular Polypody) · P. appalachianum (Appalachian Polypody) · P. attenuatum (Tapered Polypody) · P. bulbiferum (Bulblet Bladderfern) · P. californicum (California Polypody) · P. calirhiza (Nested Polypody) · P. cambricum (Welsh Polypody) · P. carthusianum (Spinulose Wood Fern) · P. dissimile (Forkvein Polypody) · P. dulce (Treetrunk Polypody) · P. exaltatum (Sword Fern) · P. falax (Crested Poly) · P. formosanum (Catepillar Fern) · P. glycyrrhiza (Licorice Fern) · P. hesperium (Western Licorice Fern) · P. hexagonopterum (Broad Beech Fern) · P. ilvense (Rusty Woodsia) · P. interjectum (Polypody) · P. lanceolatum (Lanceleaf Polypody) · P. lonchitis (Northern Holly Fern) · P. loriceum (Clambering Polypody) · P. musifolium (Polypodium) · P. pellucidum (Ae) · P. pellucidum Kaulf. var. vulcanicum Skottsb. (Dotted Polypody) · P. pellucidum var. pellucidum (Dotted Polypody) · P. pellucidum var. vulcanicum (Dotted Polypody) · P. punctatum 'Grandiceps Cobra' (Climbing Bird's Nest Fern) · P. robertianum (Limestone Oak Fern) · P. saximontanum (Rocky Mountain Polypody) · P. scouleri (Coast Polypody) · P. sibiricum (Siberian Polypody) · P. subauriculatum var. knightii (Polypodium) · P. submarginale (Brownhair Lacefern) · P. triseriale (Angle-Vein Fern) · P. virginianum (Common Polypody) · P. virginianum var. peraferens (American Wall Fern) · P. 'Green Wave' (Polypodium)

More Info

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Further Reading

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Notes

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Contributors

Data Sources

Accessed through GBIF Data Portal November 27, 2007:

Identifiers

Footnotes

  1. Alan R. Smith "Polypodiaceae". in Flora of North America Vol. 2. Oxford University Press. Online at EFloras.org. [back]
  2. Christopher H. Haufler, Michael D. Windham, Frank A. Lang, S. A. Whitmore "Polypodium". in Flora of North America Vol. 2. Oxford University Press. Online at EFloras.org. [back]
Last Revised: 7/15/2012