Hymenophyllum baldwinii D. C. Eaton; Callistopteris baueriana sensu auct., non (Endl.) Copel.; Macroglena toppingii 0. Deg. & I. Deg.; Trichomanes meifolium sensu Hillebr., non Bory; T. rigidum sensu A. Heller, non Sw.
Endemic
Name honors the Honorable D. D. Baldwin (1789-1886), ordained minister in Lahaina and self-taught physician, with a great interest m the cryptogamic vegetation of the Hawaiian Islands and who collected the type specimen.
Plants small to medium-sized, finely dissected. Caudices decumbent to upright, often small but up to 5 x 1.5 cm. Fronds clustered at tips of rhizomes, spreading, forming rosettes, often small, but up to 50 x 14 cm. Stipes shorter than blades, lower stipes with dark brown to black hairs. Blades 3-to 4-pinnate, lanceolate to ovate-lanceolate, 1 cell thick except for veins; rachises with scattered hairs. Pinnae up to 18 pairs, lower pinnae usually smaller. Ultimate segments usually narrow, deeply cut, less than 1 mm wide (sometimes wider in small forms on mossy rocks and cinder banks). Indusia cone-shaped with small, flared lips at tips of segments.
Locally common on wet banks or on soil in wet, mossy forests and along stream banks in mesic forests, 300-1,600 m, all major islands.
Callistopteris baldwinii is extremely variable in size, being small on wet banks and much larger when growing on wet forest floors. The smaller form has been recognized as Hymenophyllum baldwinii and the larger as Macroglena toppingii. Enzyme studies of the two forms suggest that they are genetically identical (Don Farrar, personal commu-nication). On Kaua 'i there is a form with wider ultimate segments and larger sori.
Callistopteris baldwinii appears to be specifically distinct from C. baueriana (Endl.) Copel., which is found only on Norfolk and Lord Howe Islands but has been recognized as also occurring in Hawai 'i by some authors. The relationship of this fern to Trichomanes meifolium Blume and T. apiifolium C. Presl, species with wider distribution in the Pacific, needs further study. It is being treated here as an endemic species.
Callistopteris baldwinii produces abundant gametophytes in Hawai 'i; though seldom recognized, they may be more common than the sporophytes. The ribbonlike gametophytes, usually found on shaded, damp cinder walls of valleys and streams, are most often found with no sporophytes nearby.
Callistopteris baldwinii may be recognized by its deeply cut, 3- to 4- pinnate, clustered fronds on decumbent to erect rhizomes, and conical-to urn-shaped indusia with small, flared lips. It sometimes resembles a miniature palm tree.
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).
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