无量山膜叶铁角蕨 wu liang shan mo ye tie jiao jue

Basionym: Asplenium wuliangshanense Ching, Acta Phytotax. Sin. 10: 186. 1965.

Plants 20-30 cm tall. Rhizome long creeping, 1.5-2 mm in diam., apex scaly; scales narrowly triangular to triangular. Fronds remote, up to 10 mm apart, green to brown-green when dry, herbaceous, subglabrous; stipe shiny, dark purplish black, 5-10 cm, base with scales similar to those on rhizome or subglabrous; lamina 1-pinnate, narrowly oblong-triangular, 12-19 × 3.5-5 cm, truncate at base, acuminate to caudate at apex; rachis shiny, purple to purplish black; pinnae 20-30 pairs, almost sessile, rectangular to trapeziform or slightly lunate, middle pinnae 1.6-2.6 × 0.5-0.7 cm, dimidiate, apex obtuse, base asymmetrical, acroscopic side truncate to cuneate and parallel to rachis, basiscopic side cut away and narrowly cuneate and entire, acroscopic margin crenate-serrate with deeply retuse teeth; pinnae spreading, basal pinnae slightly reduced. Veins distinct, forking and free, each vein ending below a marginal notch, basiscopic side with 3 or 4 veins lacking. Sori medial to inframedial, elliptic, 2-5 mm; indusia persistent, yellowish brown to deep brown, semi-elliptic, membranous, entire, opening toward costa.

● On shaded wet rocks by streams; 1900-2700 m. W Yunnan.

Hymenasplenium wuliangshanense is most similar to the following taxa: H. furfuraceum to H. changputungense. The upper margin of its pinnae is finely and regularly denticulate, with relatively deep notches (often as deep as the teeth) so that there is no obvious difference between a notch and a "normal" sinus. Hymenasplenium latidens has slightly coarser teeth and more medial sori. It is also similar to H. adiantifrons, which has a more coarsely cut margin and a more castaneous-purple rachis. Future research will have to establish the true relationships in this group. This and the following seven species form a group of related taxa that can best be distinguished by their veins that terminate below a notch in each marginal tooth. A similar taxon, Asplenium ofeliae Soldago, is known from the Philippines.