Polypodium scouleri |
Polypodium |
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coast, coast polypody, leather fern, leather-leaf fern, leather-leaf polypody, leathery polypody, leathery polypody fern, Scouler's polypody |
polypody |
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Habit | Plants on rock, occasionally terrestrial or epiphytic. | |||||||||||||||||||||||||||||||||||||||||
Stems | conspicuously whitish pruinose, stout, 3–12 mm diam., bland to slightly sweet-tasting; scales concolored to weakly bicolored, uniformly dark brown or with pale margins and base, lanceolate, symmetric, 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 85 cm. |
monomorphic, closely spaced to distant, not conspicuously narrowed at tip, to 90 cm. |
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Petiole | stout, to 3 mm diam. |
articulate to stem, straw-colored, somewhat flattened or grooved to nearly terete, winged distally. |
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Blade | ovate-lanceolate, pinnatifid, usually widest just above base, to 27 cm wide, stiff and leathery; rachis sparsely scaly to glabrescent abaxially, glabrous adaxially; scales bicolored, ovate-lanceolate, much 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 to linear, usually more than 12 mm wide; margins entire to crenulate; apex rounded to rarely broadly acute; midrib glabrous adaxially. |
linear to oblong; margins entire to serrate; apex rounded to attenuate. |
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Sori | crowded against midrib, usually more 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 | usually less than 52 µm, rugose, surface projections less than 3 µm tall. |
monolete, rugose to tuberculate. |
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Venation | anastomosing, usually forming 1 row of areoles. |
free to anastomosing, if strongly anastomosing, then never with more than 1 included veinlet in fertile areoles. |
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Sporangiasters | absent. |
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x | = 37. |
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2n | = 74, 111. |
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Polypodium scouleri |
Polypodium |
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Phenology | Sporulating late fall–spring. | |||||||||||||||||||||||||||||||||||||||||
Habitat | Cracks and ledges on cliffs, occasionally epiphytic, on a variety of substrates but preferring volcanic substrates in warmer, drier climates, rarely far from ocean | |||||||||||||||||||||||||||||||||||||||||
Elevation | 0–500 m (0–1600 ft) | |||||||||||||||||||||||||||||||||||||||||
Distribution |
CA; OR; WA; BC; Mexico in Baja California
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Worldwide |
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Discussion | The distinctive Polypodium scouleri has occasionally been assigned to the genus Goniophlebium because of its anastomosing venation and conspicuous areoles. Its venation pattern can be quite variable, however, and cannot be used as the sole feature distinguishing P. scouleri from P. californicum. Combining venation characteristics with others provided in the key distinguishes it clearly from its congeners in Polypodium. Some evidence suggests that P. scouleri hybridizes with P. californicum (S. A. Whitmore, unpubl.). I. Manton (1951) reported diploid and triploid cytotypes for P. scouleri, and variation in spore size suggests that the species may also include tetraploid populations. (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 | ||||||||||||||||||||||||||||||||||||||||||
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Name authority | Hooker & Greville: Icon. Filic. 1: 56. (1829) | Linnaeus: Sp. Pl. 2: 1082. 1753; Gen. Pl. ed. 5, 485, (1754) | ||||||||||||||||||||||||||||||||||||||||
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