Synonym(s): Asplenium baldwinii Hillebr.; A. dissectum Brack.; A. dissectum var. kauaiense Hillebr.; A. nephele-phyllum Copel.

Endemic

Greek schizo, split, deeply divided, + phyllon, leaf, alluding to the finely divided blades.

Plants medium-sized, terrestrial or epiphytic, very finely cut. Rhizomes short-creeping, decumbent. Fronds spreading, 25-75 x 15-40 em, not proliferous. Stipes close, dark brown, not glandular, often glabrous except at bases, bases sometimes with many deltate, long-linear, dark brown to black scales, and upper stipes with fibrils. Blades 4(-5)-pinnate, deltate-lanceolate, coriaceous; ra-chises with fine, dark scales and fibrils, or glabrous. Pinnae 12-20 pairs, alternate, long-deltate, long-stalked, lower pinnae equal to or slightly longer than those above. Ultimate segments very small and narrow, stalked, 5-8 x 1-2 mm, lobes 0-to 3-forked with blunt to acute tips, tips usually 2-toothed. Veins forked, 1-2 per ultimate segment. Sori 1 in somewhat concave ultimate segments, around 3 mm long. Indusia thin, wide.

Localized on mossy ground in wet forests, 750-1,700 m, uncommon on Kaua'i, where it is found in the Koke'e area, more abundant on Hawai 'i Island. This very finely dissected rain forest fern has an odd distribution pat-tern restricted to each end of the major Hawaiian Island chain. There is a local population of epiphytic plants growing in the Pu 'u Maka 'ala Forest Reserve on Hawai 'i that is otherwise typical of A. schizophyllum.

Asplenium schizophyllum, a very finely dissected fern (4(-5)-pinnate), differs from A. haleakalense by its longer, more dissected fronds; lack of glands on the stipes; shorter sori; and narrower and thinner indusia.