东洋复叶耳蕨 dong yang fu ye er jue

Aspidium yoshinagae Makino, Bot. Mag. (Tokyo) 13: 57. 1899; Phanerophlebiopsis bipinnata S. F. Wu; Polystichum yoshinagae (Makino) Makino.

Rhizome creeping, succulent at growing apex, 1-2 cm in diam., moderately scaly; scales pale brown, ovate-lanceolate, 5-8 × 1.5-3.5 cm, membranous and soft. Fronds remote or approximate, 60-95 cm; stipe stramineous, 25-45 cm, 3-5 mm in diam., base scaly as rhizome, upward scales diminishing to glabrescent; lamina (1 or)2-pinnate, yellowish green when dried, ovate-oblong or oblong-lanceolate, 35-60 × 15-25 cm, firmly papery, base cuneate, apex acuminate, rachis glabrescent; separate pinnae 10-13 pairs, alternate, with to 2 cm stalk, obliquely spreading, remote, lower 1 or 2(-4) pairs pinnate or only deeply pinnatifid, lowest pinna lanceolate and ca. 18 × 4 cm, base obliquely cuneate, apex acuminate; (primary) pinnules and ultimate segments oblong, 2-3 × 1-1.2 cm, basal pair usually smaller, base cuneate with acroscopic side slightly broader, basiscopic decurrent, apex acute, margin coarsely serrate with mucronate to aristate teeth; upper pinnae gradually reduced and sometimes slightly falcate; axes and veins with a few minute dark brown hairlike scales abaxially. Sori large, terminal on veinlets, 2-6 pairs per ultimate segment, medial between midvein and margin; indusia dark brown, firmly membranous, and entire.

Along streams in forests; 700-1200 m. Chongqing (Simian Shan), Hunan (Sangzhi, Yizhang) [Japan].

This fern differs from Arachniodes assamica in having a lamina longer than the stipe, oblong in outline, and lacking conform terminal pinna, and in having lateral pinnae linear-lanceolate with ultimate segments decurrent and basal acroscopic side slightly auriculate.