Diversity and evolution of leaf anatomical characters in Taxaceae s.l.—fluorescence microscopy reveals new delimitating characters

摘要

AbstractTaxaceaes.l.comprise six genera (includingCephalotaxus) and about 35 species; The present study aims to give new insights into the evolution of this family, especially into the phylogenetic position ofCephalotaxus. Moreover, only little is known about comparative leaf anatomy of this family and this study aims to expose and interpret the diversity and evolution of leaf anatomical characters and to assess their applicability to identify taxa at the generic and species level. A detailed phylogeny was reconstructed, using both maximum likelihood and Bayesian inference, with a combined dataset of four molecular markers from the plastid and nuclear genomes. Leaf sections from 132 specimens, representing 32 species and four varieties (fresh and herbarium material) were inspected, using fluorescence microscopy. Ancestral characters were reconstructed using Mesquite. The phylogenetic analyses provided full support forCephalotaxusas sister group to Taxaceaes.str. Within the latter, two monophyletic tribes Taxeae (comprisingAustrotaxus, Pseudotaxus, andTaxus) and Torreyeae (comprisingAmentotaxusandTorreya) were fully supported. Fluorescence microscopy was shown to be very useful for identifying leaf tissues and their constitution. We were able to show that particularly sclerified tissues have highest potential for the discrimination of both freshly collected samples and rehydrated herbarium specimens at the generic and species level. A correlation between the presence of different sclereid types could be shown and sclereids were hypothesized to pose a primitive trait in the