Morphology and molecules support the new monotypic genus Fenghwaia (Rhamnaceae) from south China

Rui-Jiang Wang,Yu-Qiang Chen,Gang-Tao Wang,Jiang-Ping Shu,Guo-Bin Jiang

doi:10.3897/phytokeys.171.57277

Abstract

Fenghwaia, a new monotypic genus, along with the new species Fenghwaia gardeniicarpa, is described from Guangdong Province, China. The combined features of inferior ovary, cylindrical drupaceous fruits and orbicular and dorsiventrally-compressed seeds with an elongate and pronounced basal appendage make the new genus significantly different from other genera of the family. In addition, its pollen morphology also showed great similarity to other species of this stenopalynous family. The molecular phylogenetic analysis, based on nuclear ribosomal internal transcribed spacer (ITS) and plastid trnL-F intron spacer (trnL-F) DNA sequence data from the new genus and the other 375 species representing 58 genera of Rhamnaceae, indicates that Fenghwaia is nested within the ‘rhamnoid’ group and sister to the tribe Rhamneae and then both sister to the tribe Maesopsideae. A taxonomic classification key to the ‘rhamnoid’ group is provided, based on morphological characters. A global conservation assessment is also performed and classifies Fenghwaia gardeniicarpa as Near Threatened (NT).

Highlights

The buckthorns (Rhamnaceae Juss.) are a cosmopolitan family of small trees, shrubs, climbers and, occasionally, herbs and are well represented both in tropical and temperate regions (Raven and Axelrod 1974)
The systematic treatment of Rhamnaceae, based on molecular data, morphological, anatomical and geographical information, indicated that Rhamnaceae should divided into three groups, viz. the ‘rhamnoid’ group, ‘ziziphoid’ group and the ‘ampelozizyphoid’ group (Richardson et al 2000a, 2004; Hauenschild et al 2016b)
Since nuclear ribosomal internal transcribed spacer region (ITS) and plastid trnL-F intron spacer region were already shown to include sufficient information to reconstruct well-supported topologies in Rhamnaceae (Hauenschild et al 2016a, b), a total of five genomic DNAs were extracted from five different individuals, using a modified cetyltrimethylammonium bromide (CTAB) method (Allen et al 2006)

Summary

Introduction

The buckthorns (Rhamnaceae Juss.) are a cosmopolitan family of small trees, shrubs, climbers and, occasionally, herbs and are well represented both in tropical and temperate regions (Raven and Axelrod 1974). This family includes approximately 900 species belonging to about 60 genera and 11 tribes. Rhamnaceae was recently revealed to be a monophyletic family and a member of the order Rosales with other eight families, viz. Rosaceae, Barbeyaceae, Dirachmaceae, Elaeagnaceae, Ulmaceae, Cannabaceae, Moraceae and Urticaceae on the basis of molecular evidence (APG IV 2016). The systematic treatment of Rhamnaceae, based on molecular data, morphological, anatomical and geographical information, indicated that Rhamnaceae should divided into three groups, viz. the ‘rhamnoid’ group, ‘ziziphoid’ group and the ‘ampelozizyphoid’ group (Richardson et al 2000a, 2004; Hauenschild et al 2016b)

Methods

Results

Conclusion