无盖轴脉蕨 wu gai zhou mai jue

Aspidium subsageniaceum Christ, Bull. Acad. Int. Géogr. Bot. 16: 240. 1906; Ctenitopsis austrosinensis (Christ) C. Christensen & Tardieu; C. subsageniacea (Christ) Ching; Dryopteris austrosinensis Christ; D. subsageniacea (Christ) C. Christensen; Heterogonium austrosinense (Christ) Tagawa; H. subsageniaceum (Christ) Holttum; Tectaria austrosinensis (Christ) C. Christensen.

Plants terrestrial, 150-200 cm tall. Rhizome erect, short, 2-2.5 cm in diam., densely scaly at apex and stipe bases; scales dark brown, broadly lanceolate, 10-12 mm, membranous, entire, apices long acuminate. Fronds clustered; stipe deep brown, glossy, 40-50 cm, ca. 1 cm in diam. at base, grooved above, with sparse broadly lanceolate brown scales upward. Lamina brown when dried, oblong, gradually narrowed toward apex, 100-150 × 30-45 cm, herbaceous, both surfaces glabrous, margins ciliate on teeth; rachises deep brown, with sparse linear scales adaxially, densely clothed with articulate brown hairs abaxially; costae and main veins densely clothed with articulate brown hairs adaxially, glabrescent abaxially; bases subcuneate, apices acuminate, bipinnatifid; pinnules ca. 20 pairs, alternate, applanate, subsessile, linear-lanceolate, middle pinnules 18-22 × 3-4 cm, pinnatipartite to 2/3, basal 2 or 3 pairs of pinnules slightly shortened and deflexed; lobes ca. 20 pairs, subapplanate, interval 2-3 mm, falcate-oblong, 1-1.5 × 7-8 mm, entire, obtuse or mucronate. Veins pinnate, 7-9 pairs, free or connected with veinlets from costa. Sori orbicular to elliptic, at middle of veinlets, in 2 irregular rows beside main veins, exindusiate.

Limestone gaps in dense forests; 100-1500 m. Guangxi, Guizhou, Yunnan [N Vietnam].