台湾肿足蕨 tai wan zhong zu jue

Plants 55-70 cm tall. Rhizomes prostrate, stout, densely scaly together with swollen stipe base; scales reddish brown, lustrous, linear-lanceolate, 1-2.5 cm, membranous, margin entire. Fronds subclustered; stipe stramineous, lustrous, 25-30 cm × ca. 2 mm, upward glabrous; lamina triangular-ovate, 30-40 cm, up to 30 cm wide at base, thinly herbaceous, densely covered with short hairs on both surfaces, rachis, costae, and costules, 4-pinnate at base, 3-pinnate upward, acuminate and pinnatifid at apex; pinnae ca. 12 pairs, spreading; lower 1 or 2 pairs opposite, separated from each other for ca. 8 cm, long stalked; upper pairs alternate or subopposite, 2-3 cm apart, shortly stalked; basal pair largest, narrowly triangular, ca. 20 cm, up to ca. 12 cm wide at base, base rounded, with ca. 1.5 cm stalk, 3-pinnate, apex acuminate; pinnules ca. 12 pairs, anadromous, alternate, spreading, acroscopic ones slightly smaller, proximal basiscopic pair largest, oblong-deltoid, ca. 8 × 6 cm, shortly stalked, base subcordate, 2-pinnate, apex acuminate; ultimate pinnules 5-8 pairs, oblique, oblong, basal one 4-5 × ca. 2.5 mm, margin pinnate into oblong lobes or crenate. Veins obvious on both surfaces, pinnate, ending at margin. Sori small, orbicular, 2 or 3 pairs per ultimate pinnule, located at middle of veinlets; indusia reddish brown, orbicular or reniform, sparsely hairy or sometimes glabrous. Spores ellipsoid, bearing few inflated folds, glabrous.

● Taiwan.

Reviewer Ralf Knapp notes that Hypodematium taiwanense may fall within the range of variation of H. crenatum, which is rather widespread in Taiwan, but further study is needed to ascertain whether or not the two taxa are distinct.