Adenophorus is a small genus of ferns belonging to the family Polypodiaceae, placed within the subfamily Grammitidoideae. Its classification follows the Pteridophyte Phylogeny Group system of 2016 (PPG I), which reorganized many grammitid ferns previously treated under broader genera into more precisely delimited groups. The order Polypodiales is one of the largest orders of ferns, and Polypodiaceae is its largest family, comprising a diverse array of mostly epiphytic species.
The genus is notable for being entirely endemic to the Hawaiian Islands, making it one of the most geographically restricted fern genera in the world. Hawaii's volcanic, highly humid montane forests and cloud forests provide the substrate and moisture conditions these ferns depend on, and several species are adapted to life as epiphytes on trees and mossy surfaces at elevation.
As of 2025, the Checklist of Ferns and Lycophytes of the World recognizes eleven accepted species and two hybrids in Adenophorus. The genus was described by the French botanist Charles Gaudichaud-Beaupré, who documented Hawaiian flora during early 19th-century Pacific voyages. Representative members include Adenophorus tamariscinus, Adenophorus tripinnatifidus, and Adenophorus hymenophylloides.
Distribution
Adenophorus is endemic to the Hawaiian Islands, with all accepted species occurring within Hawaii's montane and cloud forest ecosystems.
Taxonomy Notes
The genus is classified in subfamily Grammitidoideae of family Polypodiaceae under the Pteridophyte Phylogeny Group (PPG I) classification of 2016. It was described by Charles Gaudichaud-Beaupré and published in 1824 in Annales des Sciences Naturelles, Botanique. GBIF records authorship as Gaudich.
