Dryopteris sandwicensis sensu auct., non (Hook. & Am.) C. Chr.; Phegopteris sandwicensis sensu Hillebr., non (Hook. & Am.) H. Mann; Polypodium clarkei Baker

Endemic

Maui, +Latin suffix -ensis, indicating place or country of growth or origin.

Plants large, terrestrial. Rhizomes erect, 8-16 cm diam. Fronds large, 75-260 cm long. Stipes grooved adaxially, straw-colored to brown, shiny, scales at bases dense, stiff, linear-lanceolate, reddish brown, long, becoming soft and flattened against upper stipes, denser when young, often deciduous with age. Blades 2-to 3-pinnate, ovate-deltate to oblong-lanceolate, light green, chartaceous, glabrous; rachises grooved, grooves connected with grooves of stipes, rachises, and costae; rachises mostly naked but with occasional small, soft, reddish brown, hair-like scales. Pinnae 12-17 pairs, stalked, alternate. Pinnules oblong-lanceolate to oblong-ovate, stalked to almost sessile. Ultimate segments lobed or crenate, lobes broad, obtuse, bases broadly cuneate, apexes acute to obtuse. Veins translucent. Sori medial to sub-marginal on distal fork of veins. Indusia absent.

Found in wet forests, 945-1,700+ m, all major islands.

Incorrectly called Dryopteris sandwicensis (and Phegopteris sandwicensis) in previous publications and checklists. The error was revealed upon examination by Fraser-Jenkins (and confirmed by me) of the type specimen at Kew labeled Polypodium clarkei, described by Baker in 1891 from material collected in Hawai 'i representing this taxon. When Polypodium clarkei was later transferred to the genus Dryopteris, the name D. clarkei had already been taken, requiring Christensen to create a new name, D. mauiensis. Hillebrand (1888) erroneously called the plant Phegopteris sandwicensis, but his description under that name obviously expresses the current concept of D. mauiensis and not that of D. sandwicensis. For a further discussion of the name corrections, see D. sandwicensis.

Dryopteris mauiensis may be recognized by its large, herbaceous blades; 2-to 3-pinnate, light green fronds; characteristic stipe scales; and lack of indusia.