Author: C. Presl, 1836
Description
Rhizome bearing scales and hairs or only scales. Roots borne on all sides of rhizome. Scales glabrous or bearing multiseptate hairs, basifixed with broad base, base not cordate. Stipes articulated at the base to phyllopodia, grooved or not, glabrous. Lamina compound, tripinnate or quadripinnate (rarely in small plants bipinnate) towards base and in the middle part, deltoid and broadest towards base, glabrous (sometimes minute hairs present), not or slightly dimorphous (often fertile leaves more strongly dissected). Pinnae deltoid or narrowly triangular. Pinnules of at least the larger pinnae anadromous. Pinnules or pinnalobes narrowly ovate. Rachis adaxially side grooved. Leaf axes glabrous (sometimes a few minute hairs present). Veins in ultimate lobes simple, not reaching the margin. False veins not present. Sori indusiate, frequently single on a segment, terminal on the veins. Indusium scale-like, either attached at the narrow, cordate base only, or attached at the base and only part of the sides.
Chromosomes
In Leucostegia x = 41, the chromosome counts indicate that Leucostegia immersa in India and Taiwan is diploid (Tryon and Lugardon, 1991: 374).
Note
From the spores it would appear that Leucostegia immersa in the Philippines and New Guinea is diploid, although the chromosome reports indicate that the examined plants from India and Taiwan are haploid. The spores of Leucostegia pallida are small indicating the plants being haploid. It could well be that the greatly varying size, from plants of less than 20 cm to well over 1 m, in bot species, is due to polyploidization. More research is needed. The distribution of the two species is an indication that they might represent two varieties. The differences are very small, and lay mainly in the indusium.