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downy maiden fern, downy shield fern, tapering tri-vein fern

bog fern, Massachusetts fern, thélyptère simulatrice

Stems

short-creeping, 4–6 mm diam.

long-creeping, 1.5–3 mm diam.

Leaves

often somewhat dimorphic, evergreen, often closely placed, 50–150 cm, fertile leaves with longer petioles and more contracted pinnae.

monomorphic, dying back in winter, often 1 cm or more apart, fertile leaves often somewhat longer than sterile leaves, 25–80 cm.

Petiole

often purplish brown, 15–50 cm × 3–6 mm, at base with brown, linear-lanceolate, hairy scales.

straw-colored above base, 12–45 cm × 1–3 mm, at base sparsely set with tan, ovate, glabrous scales.

Blade

(25–)40–100 cm, 1–4(–6) proximal pairs of pinnae reduced, blade gradually tapered to pinnatifid apex.

lanceolate, 14–35 cm, proximal pinnae largest, or lowest pair slightly smaller, blade tapered gradually to pinnatifid apex.

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.

deeply pinnatifid to ca. 1 mm from costa, 3–10 × 1–2 cm;

segments oblong, somewhat oblique, entire;

proximal pair of veins from adjacent segments meeting margin above sinus.

Sori

round, medial to supramedial;

indusia tan, pubescent, hairs 0.1–0.3 mm;

sporangial stalks with orangish, stalked glands.

round, medial;

indusia tan, often glandular;

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 sparsely set hairs 0.2–0.4 mm primarily on costae, also of yellowish short-stalked glands less than 0.1 mm, blade tissue with numerous reddish to orangish, resinous, shiny, sessile, hemispheric glands;

blades adaxially with scattered hairs on veins.

2n

= 144.

= 128.

Thelypteris dentata

Thelypteris simulata

Habitat Damp woods Terrestrial in acid soils of shaded swamps and bogs, frequently associated with sphagnum
Elevation 0–100 m (0–300 ft) 0–100 m (0–300 ft)
Distribution
from FNA
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]
from FNA
CT; DE; MA; MD; ME; NH; NJ; NY; PA; RI; VA; VT; WI; WV; NB; NS; ON; QC
[WildflowerSearch map]
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.)

Source FNA vol. 2. FNA vol. 2.
Parent taxa Thelypteridaceae > Thelypteris > subg. Cyclosorus Thelypteridaceae > Thelypteris > subg. Parathelypteris
Sibling taxa
T. augescens, T. grandis, T. hispidula, T. interrupta, T. kunthii, T. nevadensis, T. noveboracensis, T. ovata, T. palustris, T. patens, T. pilosa, T. puberula, T. quelpaertensis, T. reptans, T. resinifera, T. reticulata, T. sclerophylla, T. serrata, T. simulata, T. tetragona
T. augescens, T. dentata, T. grandis, T. hispidula, T. interrupta, T. kunthii, T. nevadensis, T. noveboracensis, T. ovata, T. palustris, T. patens, T. pilosa, T. puberula, T. quelpaertensis, T. reptans, T. resinifera, T. reticulata, T. sclerophylla, T. serrata, T. tetragona
Synonyms Polypodium dentatum, Christella dentata, Cyclosorus dentatus, Dryopteris dentata, Dryopteris mollis, T. reducta Aspidium simulatum, Parathelypteris simulata
Name authority (Forsskål) E. P. St. John: Amer. Fern J. 26: 44. (1936) (Davenport) Nieuwland: Amer. Midl. Naturalist 1: 226. (1910)
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