Latin marginis, border, + -alis, pertaining to, alluding to the sometimes submarginal sori of this species.
Plants medium-sized, terrestrial. Rhizomes 2.2-4 cm diam., decumbent to erect. Fronds 45-115 cm long, proliferations present on upper rachises. Stipes dark brown, sparsely scaly at bases, scales linear-lanceolate to narrowly deltate, acuminate, brown to reddish brown, soon deciduous. Blades 1-pinnate-pinnatifid to 1-pinnate-pinnatisect, oblong-lanceolate, glabrous, narrowed at bases, acuminate. Pinnae 20-40 pairs, mostly opposite, basal pinnae smaller than those above, pinnae sometimes proliferous. Sari variable in location, medial to submarginal, elongate, single or double. Indusia irregularly cut.
Locally common in wet forests, 120-1,280 m, Kaua'i, Moloka'i, Lana'i, Maui, and Hawai'i.
Deparia marginalis may be distinguished from Deparia prolifera by its fronds with the lowest pinnae smaller than those above. In different populations, sori are variably located from medial to submarginal.