Stegnogramma sandwicensis Brack.; Cyclosorus sandwicensis (Brack.) Copel.; Dryopteris stegnogram-moides (Baker) C. Chr.; Phegopteris microdendron D. C. Eaton; P. polycarpa (Hook. & Am.) Hillebr.; P. polycarpa var. depauperata Hillebr.; P. polycarpa var. kauaiensis Hillebr.; Polypodium polycarpon Hook. & Am.; P. stegnogrammoides Baker; Thelypteris hawaiiensis C. F. Reed; T. stegnogrammoides (Baker) Fosberg

Common names: ho'i'o kula (P. & E.)

Endemic

Specific name from an earlier name for the Hawaiian Islands, the Sandwich Islands.

Plants medium-sized, terrestrial. Rhizomes stout, erect, scaly. Fronds 20-100 cm long. Stipes straw-colored, sparsely scaly with brown to dark brown scales at base, distal stipes mostly glabrous. Blades lanceolate, 1-pinnate, tips pinnatifid; rachises grooved adaxially, covered with abundant, short, fine, white, multicellular, sharp-tipped hairs, thick-chartaceous to coriaceous. Pinnae short-stalked to adnate, 13-45 pairs, lanceolate, dark green, basal pinnae some-times smaller, acuminate, margins crenate to lobed, lobes cut less than 1/4 of distance to costae, costules heavily covered with short, fine, multicellular, sharp-tipped hairs, abaxial surfaces pustulate, veins on adaxial surfaces with many short, sharp-tipped hairs pointing toward margins, aerophores at abaxial bases of stalks (more prominent in living plants, nearly invisible when dried). Veins pinnately arranged with about 8 paired branches, raised above pinna surfaces abaxially, usually 5-6+ pairs anasto-mosing below each sinus. Sori medial, 3-7 on either side of mid veins. Indusia absent.

Common in mesic to wet forests, often near streams, 750-2,100 m, all major islands.

Plants related to Pneumatopteris sandwicensis that are generally smaller with more obtuse leaves, are lighter in color, and have longer hairs on the stipes and rachises have been found on Maui and Hawai 'i. They grow in a pendulous manner on vertical, moist, mossy, ash stream banks between 2,300 and 4,700 m. This is probably a new taxon and needs more study and more collections. The young fronds were eaten raw, like those of ho'i'o (Diplazium sandwichianum).

Pneumatopteris sandwicensis may be distinguished from the similar-appearing, Christella cyatheoides by the presence of abundant short, fine hairs on the rachises, midribs, and upper surfaces of the pinnae; a darker green color; and generally rougher pinnae surfaces. Its frond tips-are pinnatifid; those of C. cyatheoides are similar to the lateral pinnae.