Wikstrom2009chap13.Pdf
Liverworts (Marchantiophyta) Niklas Wikströma,*, Xiaolan He-Nygrénb, and our understanding of phylogenetic relationships among A. Jonathan Shawc major lineages and the origin and divergence times of aDepartment of Systematic Botany, Evolutionary Biology Centre, those lineages. Norbyvägen 18D, Uppsala University, Norbyvägen 18D 75236, Altogether, liverworts (Phylum Marchantiophyta) b Uppsala, Sweden; Botanical Museum, Finnish Museum of Natural comprise an estimated 5000–8000 living species (8, 9). History, University of Helsinki, P.O. Box 7, 00014 Helsinki, Finland; Early and alternative classiA cations for these taxa have cDepartment of Biology, Duke University, Durham, NC 27708, USA *To whom correspondence should be addressed (niklas.wikstrom@ been numerous [reviewed by Schuster ( 10)], but the ebc.uu.se) arrangement of terminal taxa (species, genera) into lar- ger groups (e.g., families and orders) based on morpho- logical criteria alone began in the 1960s and 1970s with Abstract the work of Schuster (8, 10, 11) and Schljakov (12, 13), and culminated by the turn of the millenium with the work Liverworts (Phylum Marchantiophyta) include 5000–8000 of Crandall-Stotler and Stotler (14). 7 ree morphological species. Phylogenetic analyses divide liverworts into types of plant bodies (gametophytes) have generally been Haplomitriopsida, Marchantiopsida, and Jungerman- recognized and used in liverwort classiA cations: “com- niopsida. Complex thalloids are grouped with Blasiales in plex thalloids” including ~6% of extant species diversity Marchantiopsida, and leafy liverworts are grouped with and with a thalloid gametophyte that is organized into Metzgeriidae and Pelliidae in Jungermanniopsida. The distinct layers; “leafy liverworts”, by far the most speci- timetree shows an early Devonian (408 million years ago, ose group, including ~86% of extant species diversity and Ma) origin for extant liverworts.
[Show full text]