Aspidium hillebrandii (Carruth.) Hillebr.; Polystichum lobatum (Huds.) C. Presl f. polynesiae C. Chr.

Common names: ka 'upu, papa 'oi

Endemic                          

Name honors William Hillebrand (1821-1886), a German-born physician, who, while actively practicing medicine and later in re-tirement, produced the first flora of the Hawaiian Islands, published posthumously in 1888. The garden at his home later became Foster Botanical Garden.

Rhizomes erect, thick. Fronds 45-95( -11 0) cm long. Stipes densely covered with scales, scales large, overlapping, ovate to lanceolate, pale brown to reddish, thin: Blades 2-pinnate, lanceolate, narrowing at base, coria-ceous, glossy and dark green adaxially, dull and light green abaxially; rachises densely scaly, also with hairlike scales. Pinnae 20-40 pairs, up to 8 cm long, basal pinnae much smaller, lanceolate, acute-tipped, costae and veins abaxially covered with hairlike scales, adaxial surface glabrous. Pinnules ovate-lanceolate, with apical spines, lobes with small teeth or spines, sometimes lobes few or absent, margins cartilaginous, aeroscopic basal pinnules substantially larger than adjacent pinnules. Veins prominent on adaxial surfaces. Sori medial. Indusia prominent, peltate, firm, margins mostly entire.

Locally common in mesic open areas or forests, also found in upper-elevation rain forests, 1,400-2,060 m, on Maui and Hawai'i.

Polystichum hillebrandii may be recognized by its stiff, leathery, glossy, dark green fronds narrowed at the base and cartilaginous pinnule margins. The upper-most basal pinnules of each pinna are substantially larger than the adjacent pinnules. The stipes have large, overlapping, uniformly colored scales.