Abacopteris Fée.

Plants, medium-sized, in soil. Rhizomes long creeping, or short and decumbent, with sparse usually hairy brown scales. Fronds remote or approximate; stipes glabrous except at bases, but often (particularly when young) ± with unicellular acicular hairs; laminae usually 1-imparipinnate, sometimes simple or ternate; pinnae large, usually 3-10(-15) pairs, terminal pinna free, of similar shape as lateral ones, proximal pair not or slightly shortened, lanceolate, bases rounded or cuneate, subsessile or shortly stalked, not adnate to rachises, margins entire or thickly serrate, apices acuminate; costae evident, veinlets mostly obliquely spreading; venation meniscioid, i.e., veinlets joining into oblique square areoles between veinlets, an excurrent veinlet arising from joining point of every pair of veinlets continuous or interrupted and with hydathodes at apices. Laminae herbaceous or papery, sometimes somewhat leathery, green or dark brown when dry, often reddish (at least abaxially along rachises, costae and veinlets), usually ± with acicular and hooked hairs (at least abaxially along along rachises and costae), abaxially usually foveolate on intercostal areas. Sori orbicular, in 2 lines between veinlets, one per veinlet, if attached on distal part of veinlets then usually confluent when mature, rarely spreading throughout abaxial surface of pinnae, exindusiate or indusiate, hairy or glabrous; sporangia glabrous or with acicular hairs. Spores bilateral, reniform, perispore transparent or translucent, perispore ridged corrugate, verrucate, or echinate. x = 36.

The following taxon is excluded from the present treatment, pending further research: Pronephrium fengkaiensis B. S. Wang & S. H. Shi (Acta Sci. Nat. Univ. Sunyatseni 29: 72. 1990).

Sixty-one species: tropical and subtropical regions of Asia; 18 species (eight endemic) in China.

(Authors: Lin Youxing (林尤兴); Kunio Iwatsuki)