Leucotrichum is a fern genus in the family Polypodiaceae. It is one of about 26 genera of grammitids, an unranked clade within Polypodiaceae. The name of the genus refers to the white hairs that are usually present on the underside of the frond.
Leucotrichum was established in 2010 and has six currently recognized species. The type species for the genus is Leucotrichum organense. Four of the species had been in Lellingeria, and one, Leucotrichum mortonii, had been in the defunct genus Xiphopteris.
Leucotrichum has a disjunct distribution. Leucotrichum organense and Leucotrichum schenckii are endemic to the Atlantic moist forests of coastal southeastern Brazil. Leucotrichum mortonii is known only from Cuba and the Dominican Republic. Leucotrichum pseudomitchellae occurs in Costa Rica and Panama. Leucotrichum mitchellae ranges through Mexico, Central America, and the Caribbean. Leucotrichum madagascariense occurs in Madagascar.
In 2004, a phylogenetic study of DNA sequences of grammitids showed that a few species of Lellingeria are not closely related to the others. They are sister to a clade of 26 species which at that time were in the genus Terpsichore. This was confirmed six years later in another molecular phylogenetic study on the grammitids. In 2010, four species from Lellingeria and one from Xiphopteris were transferred to the new genus Leucotrichum. The clade of 26 species that is sister to Leucotrichum was named as a new genus, Alansmia, in 2011.
- Michael A. Sundue, Melissa B. Islam, and Tom A. Ranker. 2010. "Systematics of Grammitid Ferns (Polypodiaceae): Using Morphology and Plastid Sequence Data to Resolve the Circumscriptions of Melpomene and the Polyphyletic Genera Lellingeria and Terpsichore" Systematic Botany 35(4):701-715(15). doi:10.1600/036364410X539790 (See External links below).
- Paulo H. Labiak, Germinal Rouhan, and Michael A. Sundue. 2010. "Phylogeny and taxonomy of Leucotrichum (Polypodiaceae): A new genus of grammitid ferns from the Neotropics". Taxon 59(3):911-921.
- Tom A. Ranker, Alan R. Smith, Barbara S. Parris, Jennifer M.O. Geiger, Christopher H. Haufler, Shannon C.K. Straub, and Harald Schneider. 2004. "Phylogeny and evolution of grammitid ferns (Grammitidaceae): a case of rampant morphological homoplasy". Taxon 53(2):415-428.
- Michael Kessler, Ana Laura Moguel Velázquez, Michael A. Sundue and Paulo H. Labiak. 2011. "Alansmia, a new genus of grammitid ferns (Polypodiaceae) segregated from Terpsichore. Brittonia 63(2):233-244. doi:10.1007/s12228-010-9156-y