Synonym(s): Polystichum torresianum Gaudich.; Aspidium uliginosum Kunze; Dryopteris uliginosa (Kunze) C. Chr.; Lastrea torresiana (Gaudich.) T. Moore; Thelypteris torresiana (Gaudich.) Alston; T. uliginosa (Kunze) Ching
Naturalized
Name honors John Torrey (1796-1873), prominent early American botanist and professor at Columbia and Princeton Universities.
Plants medium-sized to somewhat large, terrestrial. Rhizomes decumbent, short-creeping. Fronds 55-150(-180) cm long, erect. Stipes straw-colored, scales at bases narrow, dark brown, soon deciduous, distally stipes glabrous, smooth. Blades 3-pinnate-pinnatifid to 3-pinnate-pinnatisect, deltate to linear-deltate, about as long as stipes; rachises glabrous, 2-grooved adaxially, grooves separated by a rounded ridge covered with fine, white, sharp-tipped hairs. Pinnae lanceolate, alternate, to 32 cm long. Pinnules arising obliquely from midrib, to 8 cm long, mostly cut to narrow wings along pinna rachises, abaxial surfaces with many scattered, white, needle-like hairs; costae with similar hairs on both surfaces. Ultimate segments crenulate to deeply lobed, lobes pointing obliquely toward tips. Sori medial, round, bearing hairs. Indusia small, inconspicuous, soon deciduous, or hidden by mature sporangia.
Occasional to locally common, found in disturbed and open areas in mesic forests, 5-1,200 m, all major islands except Moloka 'i and Lana 'i, where it may exist but has not yet been documented by collections. Macrothelypteris torresiana is native from the Old World Tropics to Madagascar and Polynesia, and has become widely naturalized in the Americas including the southern United States. Although the species was not collected in Hawai 'i until 1915, it was first reported as naturalized in 1892.
Macrothelypteris torresiana may be recognized by its finely dissected, 3-pinnate-pinnatifid (pinnatisect) blades that are about as long as its straw-colored stipes; stipe cross sections revealing 2 straplike vascular bundles; and the presence of white, sharp-tipped hairs on the rachises, costae, and undersurfaces of the pinnae.
Development of the Consortium of Pacific Herbaria and several of the specimen databases have been
supported by National Science Foundation Grants (BRC 1057303,
ADBC 1304924
and ADBC1115116).
Data Usage Policy. Continued support provided by the Symbiota Support Hub, a domain of iDigBio (NSF Award #2027654).
Copyright 2015 University of Hawai‘i.