Tapeinidium pinnatum (Cav.) C.Chr.

Rhizome short-to rather short-creeping, 2-3 mm ø; scales castaneous, with an oval basal and a long acicular uni-biseriate apical part, to c. 10-seriate at base, to 4 mm long. Leaves clustered to 1 cm apart; petioles stramineous to medium brown, mostly darker at base, or rarely quite dark, in adult plants 1-2 mm ø at base of lamina, abaxially at least in the upper half obtusely or more often acutely bi-angular, c. 10-35 cm long, ½-⅔ the length of the lamina. Lamina oblong, acuminate, simply pinnate, c. 15-75 cm long, with c. 12-30 major pinnae to a side; rachis stramineous to pale brown, abaxially sharply carinate, the keel starting at the base through coalescence of the two angles on the petiole. Pinnae coriaceous, mostly olivaceous-brown when dry, ascending, sessile, narrowly lanceolate to linear, shortly and somewhat unequally cuneate at the base, subacute to acuminate, the basal ones remote, slightly or not reduced, the upper ones gradually closer but usually at least their width apart, gradually, then just below the pinnatifid leaf-apex suddenly more strongly reduced, the terminal lobe often caudate. Major pinnae 7-22 cm long, 0.3-0.8 cm wide, shallowly serrate or more often crenate or bicrenate when fertile, serrate or biserrate when sterile, with strongly ascending teeth; costa percurrent, abaxially elevated, stramineous, acute. Veins immersed, mostly hidden, once or twice forked, oblique. Sori uninerval (rarely on two adjacent vein-ends), on the acroscopic vein-branch and then single, or on both branches, and then paired in the lobes, scarcely or not embossed. Indusium dark, subentire, pouch-shaped, ovate to transversely elongate-semi-elliptic, 0.3-1 mm long, 0.3-0.5 mm wide, falling short of the margin by its width or more. Spores medium brown, subellipsoidal to bean-shaped, smooth, c. 35 by 25 μ.

In moist forests, often by or on rocks in streams, 50-2700 m, mostly between 500 and 1000 m. Apparently a facultative rheophyte.