19.
Thelypteris tetragona
(Swartz) Small, Ferns S. E. States. 256. 1938.
Free-tip star-hair fern
Polypodium tetragonum
Swartz, Prodr., 132. 1788;
Dryopteris tetragona
(Swartz) Urban;
Goniopteris tetragona
(Swartz) C. Presl
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. 2 n = 144.
Damp woods; 0--50 m; Fla.; Mexico; West Indies in the Antilles; Central America to Panama; n South America.
