The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

Hottentot fern, spready tri-vein fern, Willdenow's fern, Willdenow's maiden fern

free-tip star-hair fern, freetip maiden fern

Stems

long-creeping, cordlike, 3–6 mm diam.

short-creeping, 3–5 mm diam.

Leaves

monomorphic, evergreen, 3–6 cm apart, 50–150(–250) cm.

somewhat dimorphic, evergreen, somewhat spaced, fertile leaves long-petioled, more erect, and with more contracted pinnae, to ca. 1.1 m. Petiole straw-colored, to 60 cm × 2–5 mm, at base sparsely set with brown, lanceolate, stellate-hairy scales.

Petiole

straw-colored to tan, 20–125 cm × 3–6 mm, scaleless.

Blade

30–125 cm, broadest at base, gradually narrowed distally to pinnatifid apex.

30–45(–55) × 15–25 cm, broadest at base, with apical pinna similar to lateral pinnae.

Pinnae

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.

6–8(–12) pairs, 7–15(–18) × 2–3 cm (fertile 1–2 cm), incised 1/2–3/4 of width;

segments 3–5 mm wide, rounded at apex;

veins 6–10 pairs, proximal pair from adjacent segments united at obtuse angle below sinus with excurrent vein ca. 0.5–1 mm to sinus.

Sori

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 lacking;

sporangia with numerous hairs 0.1 mm.

Indument

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 mostly needlelike hairs 0.1–0.3 mm on costae and veins, blade tissue glabrous on both sides.

2n

= 144.

= 144.

Thelypteris interrupta

Thelypteris tetragona

Habitat Wet roadside ditches, riverbanks, marshes, and cypress swamps Damp woods
Elevation 0–50 m (0–200 ft) 0–50 m (0–200 ft)
Distribution
from FNA
FL; LA; Mexico; Central America; West Indies in the Antilles; South America to Argentina; tropical and subtropical Asia; Africa
from FNA
FL; Mexico; West Indies in the Antilles; Central America to Panama; n South America
[BONAP county map]
Discussion

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.)

Source FNA vol. 2. FNA vol. 2.
Parent taxa Thelypteridaceae > Thelypteris > subg. Cyclosorus Thelypteridaceae > Thelypteris > subg. Goniopteris
Sibling taxa
T. augescens, T. dentata, T. grandis, T. hispidula, 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. simulata
Synonyms Pteris interrupta, Cyclosorus gongylodes, Cyclosorus interruptus, Cyclosorus tottus, Dryopteris gongylodes, T. gongylodes, T. totta Polypodium tetragonum, Dryopteris tetragona, Goniopteris tetragona
Name authority (Willdenow) K. Iwatsuki: Jap. J. Bot. 38: 314. (1963) (Swartz) Small: Ferns S. E. States 256. (1938)
Web links