Blechnum squarrosum Gaudich.; B. polystichoides Brack.; Sadleria polystichoides (Brack.) A. Heller; S. squarrosa (Gaudich.) T. Moore var. intermedia Hillebr.; S. squarrosa var. tripinnatifida Hillebr

Common names: 'apu 'u

Endemic

Latin squarrosus, rough with scales, in reference to the very scaly stipe and rachis.

Plants small to medium-sized. Rhizomes decumbent. Fronds drooping, 15-32 cm long. Stipes 4-5+ mm diam. at base, dark, thickly covered with scales along entire length, scales linear-triangular, elongate, light to dark brown to reddish brown with marginal glandular hairs. Blades 2-pinnate, lanceolate-ovate, leathery, 15-35(-70) cm long; rachises heavily clothed with scales throughout. Pinnae 8-36 pairs, linear-lanceolate, tips acute, 1.8-11 em long, shorter basally. Ultimate segments 12-25+ pairs per pinna, adnate, ovate to ovate-lanceolate, 0.3-0.6 em long, concave abaxially, slightly contracted at base, tips acute to rounded, margins with glandular hairs. Veins obscure. Sori 2 per segment, 1-3 mm long. Indusia firm.

Locally abundant terrestrial fern in its restricted habitat on steep, dark, damp banks, often near streams, 400-2,050 m, all major islands. Sadleria squarrosa may be distinguished from

S. unisora by its thicker stipes and rachises heavily clothed with wider, lighter-colored scales and its generally larger size, acute-tipped pinnae, more acute seg-ments, and greater number of segments per pinna.