RESUMO
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.
RESUMO
The major purpose of this study was to determine the chemical relationships between liverwort species belonging to the Lejeuneaceae family on the basis of sesqui- and diterpenoid composition. GC/MS analysis of the 31 liverwort specimens belonging to the Lejeuneaceae family indicated variability of the chemical composition of terpenoids depending on liverwort species. Each of the analyzed liverworts is characterized by the presence of particular compounds. However, there are some characteristic components, which can be chemical markers of this liverwort family. These are the pinguisane and monocyclofarnesane type sesquiterpenoids, the fusicoccane type diterpenoids, and also the sesquiterpene hydrocarbon, isolepidozene. Chemical data also showed the differences among liverworts classified in the two subfamilies, the Ptychanthoideae and Lejeuneoideae. All of the mentioned characteristic components are present in species of the subfamily Ptychanthoideae. On the other hand, among the characteristic components, only beta-pinguisene was detected in Cololejeunea stotleriana, Colura irrorata, and Myriocoleopsis gymnocolea classified in the subfamily Lejeuneoideae (subtribe Cololejeuneinae). The latter component was found to be a marker for members of the subtribe Cololejeuneinae. Neither isolepidozene nor the pinguisanes, fusicoccanes and monocyclofarnesanes were found in Lejeunea topoensis (subfamily Lejeuneoideae). The existence of the chemical polymorphism between both subfamilies is also evident from PCA analysis.