长羽芽胞耳蕨 chang yu ya bao er jue

Polystichum attenuatum Tagawa & Z. Iwatsuki var. subattenuatum (Ching & W. M. Chu) W. M. Chu & Z. R. He; P. mannii Hope ex Fraser-Jenkins; P. subattenuatum Ching & W. M. Chu.

Plants evergreen. Rhizome ascending, short, densely scaly; scales dimorphic; large scales castaneous, ovate or oblong, up to 1 cm × 7 mm, thick in texture, margins brown and membranous, entire, acuminate; small scales brown or middle part castaneous, lanceolate or linear-lanceolate, or middle part narrowly thickened, serrulate, teeth dark brown. Fronds up to 1 m; stipe stramineous, up to 35 cm, ca. 3 mm in diam. at base, abaxially densely scaly; scales brown, dimorphic, similar to scales on rhizome apex, gradually sparser toward lamina apex, and thickened castaneous part on large scales gradually reduced upward, sometimes large scales membranous without thickened castaneous part at middle. Lamina bipinnate, green or yellowish green when dry, adaxially darker, narrowly deltoid or slightly broadly oblong-lanceolate, base not or slightly contracted, apex long acuminate; rachis stramineous, densely scaly on both surfaces; small scales brown to dark brown, subulate-linear, easily falling off, mixed with few large scales; large scales brown, broadly lanceolate, margins fimbriate, membranous; rachis with 1 proliferous bulbil near tip, bulbil densely covered with brown scales. Lateral pinnae more than 30 pairs, attached at right angles to rachis, pinnate pinnae up to 15 pairs, upper pairs gradually contracted, pinnatipartite to pinnatilobate or only toothed, obliquely ovate-lanceolate to obliquely ovate; larger pinnae up to 10 × 3 cm, lanceolate or slightly falcate-lanceolate, acuminate to long acuminate; middle pinnae shortly stalked, other pinnae sessile; costa with narrow green wings on each lateral side, adaxially green, stramineous or greenish stramineous, both surfaces scaly, scales similar to rachis scales. Pinnules fewer than 10 pairs, obliquely ovate, apices acuminate, obtuse, or mucronate, all acroscopic bases with distinct deltoid auricles, basiscopic side curved, margins shallowly pinnatilobate or toothed, lobes and teeth acute apically, basal acroscopic pairs obviously larger, oblong, acroscopic margins shallowly pinnatilobate to pinnatifid, curved, basiscopic only toothed or pinnatilobate, often recurved, acroscopic side often overlapping rachis, basal basiscopic pinnules often smaller, basal basiscopic pinnules smallest; abaxially with few microscales; microscales light brown, subulate, thinly membranous; frond texture thickly papery; venation of pinnules and apical pinnae bipinnate, rarely 1-pinnate, visible abaxially, indistinct adaxially; veinlets free, simple or forked. Sori small, terminal on shorter veinlets, closer to midribs of pinnules, in 1 row on each side of midrib of upper part of pinnules, often 2 or 3 pairs on pinnule auricles and lower lobes of basal acroscopic pinnules; indusia present, entire, centers concave, brown when mature, margins sometimes shallowly lobed.

Broad-leaved evergreen forests in valleys; 1400-2200 m. Guangxi, Guizhou, Yunnan [NE India, Myanmar, Thailand, Vietnam].

One of the important differences between Polystichum attenuatum and P. lentum is that the large scales of the former are entire while those of the latter are denticulate.

Polystichum subattenuatum should be conspecific with P. attenuatum. It has continuous distribution from Thailand to S China.