Thelypteris dentata |
Thelypteris subg. Cyclosorus |
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downy maiden fern, downy shield fern, tapering tri-vein fern |
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Stems | short-creeping, 4–6 mm diam. |
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Leaves | often somewhat dimorphic, evergreen, often closely placed, 50–150 cm, fertile leaves with longer petioles and more contracted pinnae. |
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Petiole | often purplish brown, 15–50 cm × 3–6 mm, at base with brown, linear-lanceolate, hairy scales. |
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Blade | (25–)40–100 cm, 1–4(–6) proximal pairs of pinnae reduced, blade gradually tapered to pinnatifid apex. |
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Pinnae | 7–17 × 1–3 cm, incised 1/2–3/4 of width; segments rounded at apex, basal acroscopic segment of proximal pinnae often auriculate; proximal pair of veins from adjacent segments united at obtuse angle below sinus with excurrent vein 2–4 mm. |
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Sori | round, medial to supramedial; indusia tan, pubescent, hairs 0.1–0.3 mm; sporangial stalks with orangish, stalked glands. |
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Indument | abaxially of uniformly short hairs 0.1–0.2 mm on costae, veins, and blade tissue; veins adaxially with stouter hairs, also with hairs 0.1–0.2 mm on blade tissue. |
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Distinguished | from other subgenera by the combination of evergreen leaves, usually long- to short-creeping stems more than 5 mm diam., pinnate-pinnatifid blades with proximal pinnae usually not shortened (except Thelypteris hispidula and T. dentata), and some veins meeting margin at or below the sinuses. |
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x | = 36. |
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2n | = 144. |
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Thelypteris dentata |
Thelypteris subg. Cyclosorus |
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Habitat | Damp woods | |
Elevation | 0–100 m (0–300 ft) | |
Distribution |
AL; FL; GA; KY; LA; s Mexico; West Indies in the Antilles; South America to n Argentina; native to tropical and subtropical Asia; Africa [Introduced in North America] |
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Discussion | Thelypteris dentata probably does not persist northward in areas (such as Kentucky) where winters are sometimes severe (R. Cranfill 1980). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Species 7–12 were monographed by A. R. Smith (1971), who treated them in Thelypteris sect. Cyclosorus. These same species were placed in Christella sect. Pelazoneuron by R. E. Holttum (1982, p. 553), who restricted use of Cyclosorus to Thelypteris interrupta (species 15 here) and two other species. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 2. | FNA vol. 2. |
Parent taxa | Thelypteridaceae > Thelypteris > subg. Cyclosorus | Thelypteridaceae > Thelypteris |
Sibling taxa | ||
Subordinate taxa | ||
Synonyms | Polypodium dentatum, Christella dentata, Cyclosorus dentatus, Dryopteris dentata, Dryopteris mollis, T. reducta | subg. Cyclosorus |
Name authority | (Forsskål) E. P. St. John: Amer. Fern J. 26: 44. (1936) | (Link) C. V. Morton: Amer. Fern J. 53: 153. (1963) |
Web links |