title: The sporophyte-less filmy fern of eastern North America Trichomanes intricatum (Hymenophyllaceae) has the chloroplast genome of an Asian species.
abstract: Trichomanes intricatum, the sporophyte-less filmy fern of the eastern United States, has been considered to be a species whose sporophyte generation has become extinct or is possibly still present among the many species of Trichomanes s.l. in the new world tropics but unable to grow in a temperate climate. A close relationship to Asian species has heretofore not been considered. Comparison of rbcL and rps4-trnS sequences to species of Trichomanes s.l. reveals that T. intricatum shares its chloroplast genome with Crepidomanes schmidtianum of eastern Asia. Because C. schmidtianum is a sterile triploid and the ploidy level of T. intricatum is unknown, several scenarios leading to their sharing of these maternally inherited genes must be explored.
authors.affiliation: Department of Botany, National Museum of Nature and Science, 4-1-1 Amakubo, Tsukuba 305-0005, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ebihara
authors.forename: Donald R
authors.initials: DR
authors.lastname: Farrar
authors.forename: Motomi
authors.initials: M
authors.lastname: Ito