Thelypteris dentata |
Thelypteris augescens |
|
---|---|---|
downy maiden fern, downy shield fern, tapering tri-vein fern |
abrupt-tip maiden fern |
|
Stems | short-creeping, 4–6 mm diam. |
creeping, 4–8 mm diam. |
Leaves | often somewhat dimorphic, evergreen, often closely placed, 50–150 cm, fertile leaves with longer petioles and more contracted pinnae. |
monomorphic, evergreen, (0.5–)1–3.5 cm apart, (30–)65–140 cm. |
Petiole | often purplish brown, 15–50 cm × 3–6 mm, at base with brown, linear-lanceolate, hairy scales. |
straw-colored, 15–70 cm × 2–7(–9) mm, at base with scales tan to brownish, linear-lanceolate, hairy at margin. |
Blade | (25–)40–100 cm, 1–4(–6) proximal pairs of pinnae reduced, blade gradually tapered to pinnatifid apex. |
30–70 cm, broadest at or near base, abruptly narrowed distally, apical pinna ± similar to lateral pinnae, 5–17 × 1–3(–5) cm. |
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. |
(4–)10–22(–28) × (0.3–)0.7–1.5 cm, incised 1/2–3/4 of width; segments somewhat curved, margins revolute, those at base of proximal pinnae slightly elongate; proximal pair of veins from adjacent segments running to sinus. |
Sori | round, medial to supramedial; indusia tan, pubescent, hairs 0.1–0.3 mm; sporangial stalks with orangish, stalked glands. |
round, medial to supramedial; indusia tan, bearing hairs 0.2–0.4 mm; sporangia glabrous. |
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. |
abaxially of hairs 0.2–0.4 mm on costae, veins, and blade tissue, also of brownish scales 0.6–1.2 mm on costae; veins and blade tissue glabrous adaxially. |
2n | = 144. |
= 144. |
Thelypteris dentata |
Thelypteris augescens |
|
Habitat | Damp woods | Limestone banks, in sun or partial shade |
Elevation | 0–100 m (0–300 ft) | 0–50 m (0–200 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] |
FL; s Mexico; West Indies in the Bahamas; Cuba; Central America in Guatemala |
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.) |
Thelypteris augescens occasionally hybridizes with T. kunthii and T. ovata var. ovata in southern Florida. (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 > subg. Cyclosorus |
Sibling taxa | ||
Synonyms | Polypodium dentatum, Christella dentata, Cyclosorus dentatus, Dryopteris dentata, Dryopteris mollis, T. reducta | Aspidium augescens, Christella augescens, Dryopteris augescens |
Name authority | (Forsskål) E. P. St. John: Amer. Fern J. 26: 44. (1936) | (Link) Munz & I. M. Johnston: Amer. Fern J. 12: 75. (1922) |
Web links |