光轴紫柄蕨 guang zhou zi bing jue

Dryopteris subaurita Tagawa, Acta Phytotax. Geobot. 1: 157. 1932; Phegopteris subaurita (Tagawa) Tagawa; Thelypteris subaurita (Tagawa) Ching.

Plants 50-120 cm tall. Rhizome shortly creeping to ascending, apex and stipe base with dense brown linear-lanceolate hairy scales. Fronds clustered or slightly spaced; stipe red-castaneous at least at base, 10-35 cm, abaxially sparsely hairy, adaxially with dense hairs along groove; lamina oblong-lanceolate, 40-55(-100) × 15-30 cm, tapering at base, pinnate-pinnatifid, pinnatifid and long acuminate at apex; pinnae 15-20 pairs, opposite, obliquely spreading, sessile, basal pair of pinnae smallest, narrowly triangular, 2-6 × 3-6 cm, more distal pinnae gradually longer, second pair 8-15 × ca. 2 cm (excluding basalmost segments), triangular-lanceolate, bases abruptly widened to 7 cm, asymmetrically hastate, pinnatifid nearly to costules, apices acuminate; segments 15-25 pairs per pinna, opposite, obliquely spreading, basal pair clearly longer than distal pairs, particularly basiscopic one pinnatifid and more oblique, lanceolate, to ca. 4 × 1.2 cm, tapering to an acute apex, acroscopic one parallel to rachis, to 4 cm, more distal segments to 3 × ca. 0.8 cm, oblong, margins crenate to lobed, distal segments entire, obtuse or subacute at apices. Veins visible abaxially, lateral veins simple or forked on proximal larger segments, basal pair arising from bases of costae. Fronds herbaceous, drying yellowish green, with fine acicular hairs on both surfaces, hairs along costae and veins denser abaxially. Sori suborbicular to oblong, borne at middle or above middle (closer to margin) of ultimate veins. Sporangia each often with 1 or 2 short hairs below annulus. 2n = 62.

Forests beside streams, open areas in thickets; 200-1000 m. N and S Taiwan [Japan (Ryukyu Islands)].

Pseudophegopteris subaurita is closely related to P. pyrrhorhachis and to P. aurita but is seemingly absent from mainland China.