Monographs Details: Thelypteris hispidula (Decne.) C.F.Reed
Authority: Proctor, George R. 1989. Ferns of Puerto Rico and the Virgin Islands. Mem. New York Bot. Gard. 53: 1-389.
Description:Species Description - Rhizome short, erect, 3-5 mm thick (excluding root mass and tightly adhering stipe bases), bearing at apex a tuft of linear-lanceolate, lustrous dark brown to castaneous scales 3-6(-8) mm long and less than 0.7 mm wide, minutely ciliate and often with a few tiny hairs on the surfaces. Fronds spreading, not dimorphic; stipes mostly 10-40 cm long, straw-colored, sometimes darkened at base, pubescent and with a few scales near base. Blades oblong-elliptic or oblanceolate, 18-55(-75) cm long, 7-32 cm broad, tapering evenly to the short, pinnatifid apex; largest pinnae 3.5-16 cm long, mostly 0.8-2 cm wide (excluding enlarged basal segments), sessile, pinnatifid; segments oblong, slightly oblique or sometimes subfalcate, mostly ca. 3 mm wide, entire or minutely crenulate toward apex; veins usually 5-9 pairs, simple except in enlarged basal segments. Sori about medial; indusium orbicular-reniform, densely pubescent; sporangia glabrous but their stalks often bearing minute stipitate glands.
Basionym. Aspidium hispidulum Decaisne, Nouv.
Ann. Mus. Hist. N a t 3: 346. 1835.
Type. Guichenot, from Timor (P, not seen).
Syn. Nephrodium quadrangulare Fee, Mem. foug, 5:
308, 1852, (Type, Leprieur, from French
Guiana, NY, isotype.)
Bryopteris quadrangularis (Fee) Alston ex Box &
Alston, J. Bot. 75: 253. 1937.
Cyclosorus quadrangularis (Fee) Tardieu-Blot,
Notul. Syst. (Paris) 14: 345. 1953.
Thelypteris quadrangularis (Fee) Schelpe, J. S. African
Bot. 30: 196. 1964.
Two varieties of this variable species have been
found in Puerto Rico, These can usually be distinguished
a. Basal veins of adjacent segments united below
the sinus, giving forth an excurrent veinlet leading
to or toward the sinus.
b. Fronds usually more than 60 cm long; blade
less than twice as long as stipe, and with only
I or 2 pairs of slightly reduced proximal pinnae;
tissue usually hairy on adaxial side. ...
18a. var. hispidula.
b. Fronds usually less than 60 cm long; blade 2-
4 times as long as stipe, and with several pairs
of gradually reduced proximal pinnae; tissue
usually lacking hairs on adaxial side
18b. var. inconstans.
a. Basal veins of adjacent segments free or connivent
at or near the sinus, or else some free and
18b. var. inconstans.