Thelypteris tetragona

(Swartz) Small

Ferns S. E. States 256. 1938.

Common names: Free-tip star-hair fern
Basionym: Polypodium tetragonum Swartz Prodr., 132. 1788
Synonyms: Dryopteris tetragona (Swartz) Urban Goniopteris tetragona (Swartz) C. Presl
Treatment appears in FNA Volume 2.

Stems short-creeping, 3–5 mm diam. Leaves 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. Blade 30–45(–55) × 15–25 cm, broadest at base, with apical pinna similar to lateral pinnae. Pinnae 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. Indument abaxially of mostly needlelike hairs 0.1–0.3 mm on costae and veins, blade tissue glabrous on both sides. Sori round, medial to supramedial; indusia lacking; sporangia with numerous hairs 0.1 mm. 2n = 144.

Habitat: Damp woods
Elevation: 0–50 m


V2 395-distribution-map.gif

Fla., Mexico, West Indies in the Antilles, Central America to Panama, n South America.


Selected References


Lower Taxa

... more about "Thelypteris tetragona"
Alan R. Smith +
(Swartz) Small +
Polypodium tetragonum +
Free-tip star-hair fern +
Fla. +, Mexico +, West Indies in the Antilles +, Central America to Panama +  and n South America. +
0–50 m +
Damp woods +
Ferns S. E. States +
Dryopteris tetragona +  and Goniopteris tetragona +
Thelypteris tetragona +
Thelypteris subg. Goniopteris +
species +