Polypodium virginianum |
Polypodium |
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common polypody, polypode de virginie, rock polypody, tripes-de-roches |
polypody |
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Habit | Plants on rock, occasionally terrestrial or epiphytic. | |||||||||||||||||||||||||||||||||||||||||
Stems | often whitish pruinose, slender, to 6 mm diam., acrid-tasting; scales weakly bicolored, lanceolate, contorted distally, base and margins light brown, sometimes with dark central stripe, margins denticulate. |
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. |
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Leaves | to 40 cm. |
monomorphic, closely spaced to distant, not conspicuously narrowed at tip, to 90 cm. |
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Petiole | slender, to 2 mm diam. |
articulate to stem, straw-colored, somewhat flattened or grooved to nearly terete, winged distally. |
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Blade | oblong to narrowly lanceolate, pinnatifid, usually widest near middle, occasionally at or near base, to 7 cm wide, somewhat leathery; rachis sparsely scaly to glabrescent abaxially, glabrous adaxially; scales lanceolate-ovate, usually more than 6 cells wide. |
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. |
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Segments | oblong, less than 8 mm wide; margins entire to crenulate; apex rounded to broadly acute; midrib glabrous adaxially. |
linear to oblong; margins entire to serrate; apex rounded to attenuate. |
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Sori | midway between margin and midrib to nearly marginal, less than 3 mm diam., circular when immature. |
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. |
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Spores | more than 52 µm, tuberculate, surface projections more than 3 µm tall. |
monolete, rugose to tuberculate. |
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Venation | free. |
free to anastomosing, if strongly anastomosing, then never with more than 1 included veinlet in fertile areoles. |
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Sporangiasters | present, usually less than 40 per sorus, heads covered with glandular hairs. |
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x | = 37. |
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2n | = 148. |
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Polypodium virginianum |
Polypodium |
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Phenology | Sporulating summer–fall. | |||||||||||||||||||||||||||||||||||||||||
Habitat | Cliffs and rocky slopes, on a variety of substrates | |||||||||||||||||||||||||||||||||||||||||
Elevation | 0–1800 m (0–5900 ft) | |||||||||||||||||||||||||||||||||||||||||
Distribution |
AL; AR; CT; DC; DE; GA; IA; IL; IN; KY; MA; MD; ME; MI; MN; MO; NC; NH; NJ; NY; OH; PA; RI; SC; SD; TN; VA; VT; WI; WV; AB; MB; NB; NF; NS; NT; ON; PE; QC; SK; SPM
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Worldwide |
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Discussion | Traditionally, two cytotypes have been recognized within Polypodium virginianum (I. Manton and M. Shivas 1953). Recent research has demonstrated that the tetraploid cytotype, which properly bears the name P. virginianum (R. Cranfill and D. M. Britton 1983), is an allopolyploid produced by hybridization between the diploid cytotype (here called P. appalachianum) and P. sibiricum (C. H. Haufler and M. D. Windham 1991; C. H. Haufler and Wang Z. R. 1991). Although sometimes similar to its diploid parents in overall leaf morphology, P. virginianum has consistently larger spores, typically more than 52 µm (see additional comments under P. appalachianum and P. sibiricum). Frequent hybridizations between P. virginianum and P. appalachianum form morphologically intermediate, triploid individuals with misshapen spores. Sterile triploids also result from hybridization between P. virginianum and P. sibiricum. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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. We have not included the European Polypodium cambricum Linnaeus [P. australe Fée], reported from San Clemente Island, California (R. M. Lloyd and J. E. Hohn 1969), in the North American flora because, since the single, original collection, efforts to relocate specimens in nature have failed (R. M. Lloyd et al. 1992). Because taste is a characteristic used in the descriptions, the reader is cautioned to taste clean rhizomes from uncontaminated soils. Species ca. 100 (11 in the flora). (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 | Polypodiaceae > Polypodium | Polypodiaceae | ||||||||||||||||||||||||||||||||||||||||
Sibling taxa | ||||||||||||||||||||||||||||||||||||||||||
Subordinate taxa | ||||||||||||||||||||||||||||||||||||||||||
Synonyms | P. vinlandicum, P. vulgare var. americanum, P. vulgare var. virginianum | |||||||||||||||||||||||||||||||||||||||||
Name authority | Linnaeus: Sp. Pl. 2: 1085. (1753) | Linnaeus: Sp. Pl. 2: 1082. 1753; Gen. Pl. ed. 5, 485, (1754) | ||||||||||||||||||||||||||||||||||||||||
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