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

Abstract

Taxaceae s.l. comprise six genera (including Cephalotaxus) and about 35 species; The present study aims to give new insights into the evolution of this family, especially into the phylogenetic position of Cephalotaxus. 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 for Cephalotaxus as sister group to Taxaceae s.str. Within the latter, two monophyletic tribes Taxeae (comprising Austrotaxus, Pseudotaxus, and Taxus) and Torreyeae (comprising Amentotaxus and Torreya) 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 evolution of Taxaceae s.l. New identification keys were generated on the basis of leaf anatomical characters. The microscopic method presented here is applicable for further studies within gymnosperms and probably in angiosperms, as well.

A permineralized Early Cretaceous lycopsid from China and the evolution of crown clubmosses

“…to compile a representative sample of the current global morphological, functional, and diversity of lycopsids. Anatomy was assessed following the procedure of Ayensu (1967) (see also Elpe et al ., 2018). Dried leafy stems were soaked and softened in a 6 : 1 mixture of aerosol–OT (10%, w/v) and acetone (95%, v/v) for at least 72 h, then stored in 70% ethanol in plastic vials.…”

Characterization of complete chloroplast genome of Amentotaxus yunnanensis (Taxaceae), a species with extremely small populations in China

“…Conifers have dominated forests for more than 200 million years and are very important for the ecosystem and human society (Nystedt et al 2013). Taxaceae is a small family of conifers comprises of six genera (including Amentotaxus, Austrotaxus, Cephalotaxus, Pseudotaxus, Taxus, and Torreya) and about 35 species (Elpe et al 2018). The genus Amentotaxus Pilg.…”

RNAseq‐based phylogenetic reconstruction of Taxaceae and Cephalotaxaceae

“…(). Recently, a sister relationship has also been established between them using fluorescence microscopy of leaf anatomy (Elpe et al., ). Although Taxaceae and Cephalotaxaceae show similarity in several morphological features, they differ widely in others.…”