2. Diplopterygium (Diels) Nakai, Bull. Natl. Sci. Mus., Tokyo. 29: 47. 1950.
里白属 li bai shu
Authors: Jin Xiaofeng, Bingyang Ding & Kunio Iwatsuki
Gleichenia sect. Diplopterygium Diels in Engler & Prantl, Nat. Pflanzenfam. 1(4): 353. 1900.
Rhizomes long creeping, branched, with protosteles, covered with scales; scales brown, lanceolate, margin entire or ciliate. Fronds distant; rachis undivided, producing 1 to several successive pairs of pinnae; stipe and rachis with lanceolate scales and stellate hairs when young, these glabrescent or persistent; dormant apical bud with dense brown scales, outer bracts pinnatifid, leaflike; primary pinnae opposite, 2(or 3)-pinnatifid, spreading or drooping; ultimate pinnules many, obliquely or horizontally spreading, deeply pectinately pinnatifid to costa, lanceolate in outline, sessile or shortly stalked at base, apex acuminate; lobes linear to narrowly oblong-lanceolate, margin entire and slightly reflexed, apex emarginate; veins once forked with a pair in each group, spreading to lobe margins. Sori in single lines on either side of costule; sporangia 2-4; spore tetrahedral, without perispore.
About 20 species: tropical and subtropical areas, mainly distributed in tropical Asia; nine species (four endemic) in China.
The FRPS account of the Gleicheniaceae treated all species of Diplopterygium as members of the genus Hicriopteris C. Presl, but Holttum (Reinwardtia 4: 261. 1957) showed that the type of Hicriopteris belonged in Dicranopteris.
One of us (Iwatsuki) considers that Diplopterygium, as treated here, is split into too many species.
