A taxonomic reassessment of Viburnum (Adoxaceae) in the Azores

Hanno Schaefer,Luís Silva,Valéry Malécot,Mark A. Carine,Aula Lourenço,Mónica Moura

doi:10.11646/phytotaxa.210.1.3

Abstract

The taxonomic status of the Azorean endemic Viburnum tinus subsp. subcordatum is reassessed, using morphological characters and new molecular data from the ITS region and the trnK intron. A survey of morphological variation supports the recognition of V. tinus subsp. subcordatum as distinct from V. tinus subsp. tinus and the Canary endemic V. rugosum (formerly known as V. tinus subsp. rigidum) based on leaf shape, the shape of the leaf base and apex, the sub-entire and revolute leaf margins, blistered upper leaf surfaces, trichome density and type, and fruit size. Molecular data also confirm this distinctiveness within section Tinus. Taken together, our morphological and genetic data presented in this paper support the recognition of the Azorean taxon at the species level under the name of Viburnum treleasei. A description of the species is provided and nomenclatural issues relating to the two Macaronesian Viburnum taxa are discussed.

Highlights

The genus Viburnum Linnaeus (1753: 267−268) (Adoxaceae) is estimated to contain between 175 to 230 species occurring primarily in the temperate regions of the Northern Hemisphere and secondarily in subtropical portions of Asia and Latin America (Malécot 2002, Donoghue et al 2004)
Post-hoc tests showed that the Canarian material had significantly longer and wider leaves than material from the other regions, that specimens from all V. tinus subsp. tinus regions displayed significantly narrower leaves, while specimens from the Azores had a significantly different intermediate leaf width and higher width/length ratio (Table 1)
Differences between the V. tinus subsp. tinus accessions from different regions were limited to leaf shape traits that occurred with low frequencies

Summary

Introduction

The genus Viburnum Linnaeus (1753: 267−268) (Adoxaceae) is estimated to contain between 175 to 230 species occurring primarily in the temperate regions of the Northern Hemisphere and secondarily in subtropical portions of Asia and Latin America (Malécot 2002, Donoghue et al 2004). The monophyly of all sections was supported by morphological data and molecular studies, except sections Megalotinus and Odontotinus (Donoghue 1983, Baldwin et al 1995, Donoghue et al 2004, Winkworth & Donoghue 2005, Clement & Donoghue 2011, 2012, Schmerler et al 2012). Viburnum tinus Linnaeus (1753: 267−268), placed in section Tinus, is a morphologically variable taxon in which two to three subspecies have been recognised. Silva in Palhinha (1966: 115−116) that is endemic to the Azores, V. tinus subsp. A third taxon, endemic to the Canaries, has been known as Viburnum tinus L. subsp. It was resolved as sister taxon to V. tinus subsp. It was resolved as sister taxon to V. tinus subsp. tinus in studies by Clement & Donoghue (2011, 2012) and Schmerler et al (2012)

Methods

Results

Conclusion