28. Rhachidosoraceae
轴果蕨科 zhou guo jue ke
Authors: He Zhaorong & Masahiro Kato
Plants terrestrial or epilithic, evergreen, medium-sized. Rhizome erect or creeping, apex and base of stipes scaly; scales brown, lanceolate, entire, long; fronds caespitose, rarely distant or approximate. Fertile fronds up to 2 m; stipe pale stramineous, rarely red-brown, usually as long as lamina, base not thickened, with sparse scales, upward glabrous throughout. Lamina deltoid or ovate-deltoid, herbaceous, glabrous, pinnate lobes 2- or 3-pinnate or ultimate pinnules pinnate, acuminate at apex. Pinnae alternate, ascending, stipitate, pinnules anadromous, acuminate at apex, base asymmetrical or ± symmetrical. Lobes anadromous, obtuse, usually asymmetrical at base, ultimate pinnules serrate or crenate at margin, sometimes entire. Veins free, prominently, lateral veins mostly forked or pinnate on ultimate pinnules, rarely simple. Costae slightly shallowly grooved adaxially, bilateral margin with slight protuberance. Sori shortly linear, or slightly lunate, solitary on acroscopic veinlets of ultimate pinnule base, usually in 1 line per lobe, 1 or 2 pairs per lobe with pinnate veins, close to ultimate pinnules or midrib of lobes, in parallel lines with each other. Sori and indusia similar, solitary, thickly membranous, slightly swollen, pale gray or gray-green at first, then mostly becoming pale brown, entire, persistent, Spores 2-sided, semicircular in equatorial plane. Spores perispore prominent, slightly hyaline, rough, with regular or irregular filiform ornamentation, circular projection, or rarely broad flakelike folds. x = 40.
One genus and seven species: mainly distributed in subtropical and tropical areas of China, east to Japan, the Philippines, south to Vietnam and Indonesia (Sumatra); five species (three endemic) in China.
Based on molecular evidence that Rhachidosorus does not form a monophyletic group with Athyriaceae (cf. R. Sano et al., Molec. Phylogen. Evol. 15: 403-413. 2000), X. C. Zhang proposed the family Rhachidosoraceae (Phytotaxa 19: 16. 2011).
Chu Wei-ming & He Zhao-rong. 1999. Rhachidosorus. In: Chu Wei-ming, ed., Fl. Reipubl. Popularis Sin. 3(2): 267-275.
