Thelypteris interrupta
Thelypteris dentata
Hottentot fern, spready tri-vein fern, Willdenow's fern, Willdenow's maiden fern
downy maiden fern, downy shield fern, tapering tri-vein fern
long-creeping, cordlike, 3–6 mm diam.
short-creeping, 4–6 mm diam.
monomorphic, evergreen, 3–6 cm apart, 50–150(–250) cm.
often somewhat dimorphic, evergreen, often closely placed, 50–150 cm, fertile leaves with longer petioles and more contracted pinnae.
straw-colored to tan, 20–125 cm × 3–6 mm, scaleless.
often purplish brown, 15–50 cm × 3–6 mm, at base with brown, linear-lanceolate, hairy scales.
30–125 cm, broadest at base, gradually narrowed distally to pinnatifid apex.
(25–)40–100 cm, 1–4(–6) proximal pairs of pinnae reduced, blade gradually tapered to pinnatifid apex.
7–30 × 1–2 cm, incised 1/3–1/2(–3/5) of width;
segments deltate, rounded to acute;
proximal pair of veins from adjacent segments united at acute or obtuse angle below sinus, with excurrent vein 2–4 mm.
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.
round, medial to supramedial;
indusia tan, glabrous to hairy;
sporangia with red- or orange-capped, stalked, globose glands arising from sporangial stalks.
round, medial to supramedial;
indusia tan, pubescent, hairs 0.1–0.3 mm;
sporangial stalks with orangish, stalked glands.
abaxially of hairs 0.1–0.3 mm on costae and veins, or hairs often lacking, costae also with tan, ovate scales;
veins, costules, and costae adaxially glabrous or sparsely pubescent;
blade tissue without hairs on both sides, or hairy abaxially, usually with red to orange, shiny, sessile, hemispheric glands abaxially.
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.
= 144.
= 144.
Thelypteris interrupta
Thelypteris dentata
D. B. Lellinger (1985) applied the name Thelypteris interrupta to specimens from India, while using T. totta (type from South Africa) for North American and South American specimens. Diploid cytotypes are known from Africa and Asia, whereas all counts from the Neotropics are tetraploid. Until more counts are available and the morphologic variation (chiefly in glands, pubescence, and leaf size) in this species complex is better understood, I prefer to circumscribe the species broadly.
R. E. Holttum (1982) circumscribed Cyclosorus (as a genus) to include this species and one or two others.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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.)
LA Plants
WildflowerSearch
iNaturalist
USDA Plants Database
