海南耳蕨 hai nan er jue

Plants evergreen. Rhizome ascending, 0.8-1.8 cm, ca. 7 mm in diam., with remnant bases of old stipes, scaly; scales brown, ovate-deltoid or broadly lanceolate, 1.15-1.85 × 0.50-0.85 mm, subentire, with few short outgrowths and shortly ciliate; roots dull brown when dry, up to 17 cm, 0.22-0.43 mm in diam., subglabrous or densely covered with short linear and tortuous hairs. Fronds 4-10 per rhizome, appressed to substrate or slightly ascending, (13.5-)20.1-35.6 cm; stipe green, (3.6-) 6.7-10.5 cm, 0.63-1.22 mm in diam. at middle, scaly; basal stipe scales brown, concolorous, ovate-deltoid or lanceolate, papery, 1.8-3.15 × 0.6-0.95 mm, subentire or slightly ciliate, with irregular dentate outgrowths, caudate; distal stipe scales similar to basal stipe scales but narrower, brown, 1.2-2.8 × 0.4-0.7 mm, papery, margins with short outgrowths, apices caudate. Lamina 1-pinnate, adaxially green when fresh, dull green when dry, oblanceolate, (8.7-)12.9-24.3 × 3.1-4.3 cm, slightly narrowed toward base from below middle of lamina, apex acute or rounded; rachis green (same color as pinnae) when fresh, turning yellowish green when dry, 0.59-0.84 mm in diam. at middle, apex without proliferous bulbils, abaxially scaly; rachis scales light brown, nearly transparent, lanceolate or narrowly lanceolate, 1.25-2.65 mm, base 0.25-0.58 mm wide, unequal in length, membranous, sparsely toothed, caudate. Pinnae (8-)18-22 pairs, oblong, 16.9-18.6 × 7.1-9.4 mm, basalmost pairs slightly narrowed, nearly 2/3-4/5 as long as middle ones, shortly stalked, basiscopic margins at angles of 95°-120° with rachis, alternate, apices rounded, bases broadly cuneate with basiscopic side being narrower and forming an 80° angle with acroscopic side, distal acroscopic margins shallowly undulate, undulations 3 or 4, ca. 0.2 mm tall at middle and non-mucronate, acroscopic base auriculate, auricles deltoid, 3.7-5.1 × 3.1-3.4 mm, basiscopic margins entire, curved; adaxially almost glabrous, abaxially sparsely covered with microscales; microscales narrow-type, brown, linear or subulate, 1.1-2.9 × 0.11-0.18 mm at base; frond texture papery; venation pinnate, visible abaxially, slightly obscure adaxially; lateral veins free, simple or forked. Sori terminal on lateral veins, 4-8 on acroscopic side, 1-4 on distal basiscopic side, 1.4-2.4 mm in diam., close to pinna margins (centers of sori 0.6-0.8 mm from pinna margins, 1.8-3.1 mm from midrib), centers ca. 1.2 mm apart from one another; indusia brownish, (0.3-)0.8-1.2 mm in diam., membranous, irregularly lacerate, caducous.

● Wet limestone cliffs in rain forests; ca. 800 m. Hainan (Dongfang).

Polystichum hainanicola is most similar to P. guangxiense but differs in having a lower length to width ratio of the pinnae, completely fertile laminae, and fewer sori on each pinna.