梯羽耳蕨 ti yu er jue

Cyrtomium trapezoideum Ching & K. H. Shing ex K. H. Shing, Acta Phytotax. Sin., Addit. 1: 15. 1965.

Plants evergreen. Rhizome erect, densely covered with lanceolate brown scales. Fronds 35-50 cm; stipe stramineous, 20-24 cm, 2-3 mm in diam. at base; basal stipe scales dense, brown, narrowly ovate and lanceolate, with small teeth; distal stipe scales similar but smaller, gradually sparser toward stipe apex. Lamina 1-pinnate, lanceolate, 22-40 × 6-9 cm, slightly contracted at base, acuminate; rachis scales sparse, brown, linear. Pinnae 14-16 pairs, alternate, slightly ascendant, shortly stalked, rhombic-ovate, middle pinnae 3.5-5 × 1.5-2 cm, bases oblique, acroscopic margins truncate and with auricles, basiscopic margins cuneate, margins with forward-pointing acute teeth, apices acute; both surfaces glabrous; frond texture thinly leathery; venation pinnate, slightly raised abaxially, indistinct adaxially, veinlets anastomosing to form 1 row of areoles. Sori in 2 rows on each side of midrib; indusia present, entire.

● Dense forests. Guangdong (Ruyuan), Sichuan.

No molecular studies have sampled Polystichum trapezoideum yet, but based on its pinnatifid and acuminate apex of lamina, it is a member of Polystichum.