World checklist of hornworts and liverworts

Abstract

A working checklist of accepted taxa worldwide is vital in achieving the goal of developing an online flora of all known plants by 2020 as part of the Global Strategy for Plant Conservation. We here present the first-ever worldwide checklist for liverworts (Marchantiophyta) and hornworts (Anthocerotophyta) that includes 7486 species in 398 genera representing 92 families from the two phyla. The checklist has far reaching implications and applications, including providing a valuable tool for taxonomists and systematists, analyzing phytogeographic and diversity patterns, aiding in the assessment of floristic and taxonomic knowledge, and identifying geographical gaps in our understanding of the global liverwort and hornwort flora. The checklist is derived from a working data set centralizing nomenclature, taxonomy and geography on a global scale. Prior to this effort a lack of centralization has been a major impediment for the study and analysis of species richness, conservation and systematic research at both regional and global scales. The success of this checklist, initiated in 2008, has been underpinned by its community approach involving taxonomic specialists working towards a consensus on taxonomy, nomenclature and distribution.

Keywords: Anthocerophyta; Marchantiophyta; nomenclature; taxonomy.

Figure 1.

Habit images of selected lineages of Anthocerotophyta (hornworts) and Marchantiophyta (liverworts). A Phaeomegaceros squamuliger, photo by J. Hollinger B Haplomitrium mnioides, photo by L. Zhang C Conocephalum japonicum, photo by D. G. Long D Colura vitiensis, photo by T. Pócs E Pleurozia gigantea, photo by L. Söderström F Riccardia spegazziniana, photo by Juan Larraín.

Figure 2.

Number of novel liverwort species, excluding new combinations, which have been described over the last 250 years, with an inset of the number described from 2001–2012.