南亚耳蕨 nan ya er jue

Aspidium mucronifolium Blume, Enum. Pl. Javae 2: 164. 1828; A. aculeatum (Linnaeus) Swartz var. mucronifolium (Blume) C. B. Clarke; A. tacticopterum Kunze; Polystichum aculeatum (Linnaeus) Roth ex Mertens var. formosanum Kodama; P. aculeatum var. mucronifolium (Blume) Beddome; P. heteropaleaceum N. C. Nair & K. Nag; P. kodamae Tagawa; P. tacticopterum (Kunze) T. Moore.

Plants evergreen. Rhizome erect or ascending, short, densely scaly; scales brown, filiform. Fronds 40-60 cm; stipe stramineous, 11-26 cm, 4-6 mm in diam. at base, densely covered with linear and lanceolate brown scales and larger scales; large scales dense, bicolorous, middle part blackish brown, margins brown, shiny, broadly ovate and broadly ovate-lanceolate, up to 30 × 10 mm, subentire, long acuminate. Lamina bipinnate, deltoid-ovate, 21-47 × 11-22 cm near basal part, not contracted toward base, acute or slightly acuminate; rachis without proliferous bulbils, densely covered with linear, lanceolate brown scales and larger scales; large scales dense, shiny, broadly ovate and broadly lanceolate, up to 10 × 6 mm, subentire, caudate. Pinnae 16-27 pairs, alternate, ascendant, shortly stalked, lanceolate, not contracted toward base or only basiscopic side slightly contracted, bases asymmetrical, apices acuminate; middle pinnae 1-1.9 cm apart, basal pairs 8-16 × 1.8-2.8 cm, 1-pinnate; costa scaly; scales brown, linear or lanceolate. Pinnules 13-25 pairs, alternate, shortly stalked, oblong, 0.7-1.1 cm × 3-4.6 mm, bases cuneate, acroscopic margins obtuse-toothed, apices acute and mucronate; bases with rounded auricles, basiscopic margins shallowly toothed, tips of teeth shortly spinulose, basal acroscopic pinnules largest, pinnatilobate; abaxially with few lanceolate microscales, adaxially subglabrous; frond texture thinly leathery; venation pinnate on pinnules, lateral veins 6-8 pairs, dichotomous, distinct. Sori (2 or)3-5 pairs per pinnule, in 1 row on each side of midrib, terminal on veinlets, dark brown; indusia brown, membranous, irregularly toothed.

Forests, streamsides on brown soils; 1600-2400 m. Taiwan, Yunnan [Bhutan, NE and S India, N Myanmar, E Nepal, Sri Lanka, Thailand, Vietnam].

In FRPS (5(2): 55. 2001), this species was referred to as Polystichum tacticopterum. Fraser-Jenkins (Himalayan Ferns (Guide to Polystichum), 37. 1997) placed it in P. sect. Metapolystichum Tagawa.

Polystichum mucronifolium can easily be distinguished from all other species by having rather large broadly ovate and bicolorous stipe scales with blackish brown middle part, ovate and brown rachis scales, and pinnules with acroscopic margins bluntly toothed.