台湾曲轴蕨 tai wan qu zhou jue

Plants ca. 85 cm tall. Rhizome long creeping, 1.5-4.5 mm in diam., hairy, hairs castaneous, lucid, bristlelike. Fronds firmly herbaceous when dried; stipe brown, shiny, slender, 10-45 cm, slightly grooved adaxially, hispid at base, muricate apically; lamina green, 3-pinnate-pinnatifid, ovate-oblong in outline, 22-60 × 11-25 cm, abaxially sparsely pubescent, adaxially glabrous; pinnae ca. 15 pairs, alternate, decumbent, shortly stalked or subsessile, oblong-lanceolate, base subtruncate, apex acuminate; basal pair largest, 6-18 × 2.5-9 cm; rachis zigzag, straw-colored, scabrous or glabrous; pinnules many, shortly stalked or sessile, oblong-lanceolate, 1-5 × 0.5-0.8 cm, base subtruncate; ultimate pinnules 5-14 pairs, oblong or broadly subulate, to 8 × 3 mm, 2-5-aristate on each side; veins simple or 2-forked. Sori absent at segment apex; indusia linear, membranous, entire, persistent.

● Taiwan (Taidong).

Reviewer Ralf Knapp noted that this species, which is extremely rare, is generally lumped into Paesia radula (Baker) C. Christensen, described from Sumatra (e.g., C. M. Kuo, Taiwania 30: 59. 1985; Knapp, Ferns Fern Allies Taiwan, 108, 470. 2011).