|Abstract||Rhizoma breviter repens, squamis integris; petioli et rhachides glabrae. Lamina tripartita, pars medialis bipinnata, laterales semipedatae vel subsemipedatae; pinnulae tenuiter herbaceae, dimidiatae, circumscriptione ¼-elliptica, obtusae; lobi sorales hippocrepiformes, in sinibus profundis dispositi.|
Rhizome short-creeping to ascending, ca. 5 mm in diameter; scales medium brown, yellowish brown in transmittent light, very narrowly triangular, 2 mm long, 0.3 mm wide, entire. Leaves close; petiole atropurpureous or dark reddish brown, smooth, lustrous, ca. 15-40 cm long, about as long as to slightly longer than the lamina, flattened in drying but apparently adaxially shallowly channelled and somewhat pale-margined. Lamina ca. 15-30 cm long, tripartite, the middle part bipinnate, the lateral ones semipedate or subsemipedate; colour medium to dark green when dry but described as pale glaucous by the collectors; texture thinly herbaceous. Axes atropurpureous to dark reddish brown, without indument, adaxially flattened and with slightly paler margins. Central part of lamina ca. 20-27 cm long, at the base with one or a few pairs of petiolulate secondary pinnae (except in smaller, sterile, apparently not full-grown plants where it is simply pinnate), these ca. 4-8 cm long and with 5-10 pinnules to a side and a terminal one; upper part with simple, comparatively large (primary) pinnules. Lateral parts of lamina two, alternate, inserted 1-3 cm from each other and from the basal secondary pinnae of the central part, rather strongly ascending, each branching semipedately as in Adiantum pedatum L., but the basal acroscopic secondary division of the lowest point of division not always simple as in that species, but in larger leaves pinnate, with 2-8 pinnules; apart from this the lateral parts 3 or 4 times pseudodichotomously furcate; larger divisions with ca. 16-20 non-contiguous pinnules to a side. Larger (ultimate) pinnules 13 by 7 to 22 by 11 mm, twice as long as wide, dimidiate, ¼-elliptic, with straight or slightly concave lower and outward increasingly convex upper/outer margin, the basal ones with a petiolule of up to 3 mm, the upper ones subsessile; the sclerotic tissue of the petiolules extending into the pinnules, these non-articulate. Upper pinnules little reduced; terminal pinnule flabellate, asymmetric, ± lobed. Margin of sterile (parts of) pinnules with a few narrow acute incisions up to 1 mm deep, otherwise faintly sinuate; veins evident, free, 2 or 3 times forked, ca. ½ mm apart, ending between the faint bulges of the margin. Fertile pinnules with 3 to 5 soral lobes on the upper/outer margin, these usually alternating with incisions up to 1 mm deep; each lobe in a deep sinus with ± touching lips; soral lobe hippocrepiform, 1-1½ by 1 mm, receiving two veins and containing 3 to 5 veinlets, brownish and somewhat bulging at maturity. Sporangia crowded on the veinlets, with ca. 18 bow-cells; spores medium brown, ca. 50 µ across as seen from the inner side, minutely verruculose.