The significance of floral features within infrageneric classification of Euonymus (Celastraceae)

• Published in: Flora. Morphologie, Geobotanik, Oekophysiologie Vol. 242; pp. 53 - 60
• Main Authors: Yao, Chi-yuan, Du, Cheng, Zuo, Yun-juan, Liu, Quan-ru, Ma, Jin-shuang
• Format: Journal Article
• Language: English
• Published: Elsevier GmbH 01.05.2018
• Subjects: Axile placentation; Floral characters; Morphology; Ovule number; Taxonomy; Ovule number; Floral characters; Taxonomy; Morphology; Axile placentation
• ISSN: 0367-2530; 1618-0585
• DOI: 10.1016/j.flora.2018.02.011

•We propose the three subtypes of axile placentation firstly based on the precise anatomical observations of Euonymus species.•Flower merosity, petal color and ovule number per locule are proved to be more reasonable evidence in Euonymus classification.•The present study provides the floral morphological dataset of many species that have not been sampled before in Euonymus. Euonymus is a highly diverse and cosmopolitan genus within Celastraceae. Floral anatomy of twenty-eight Euonymus taxa were investigated to examine whether floral features provide useful information for infrageneric classification using light microscopy and scanning electron microscopy. The floral characters were evaluated by cluster and principal coordinate analysis. Flower merosity, petal color, and ovule number per locule were of potential systematic value as supported by ordination analysis. In addition, morphological data on the ovary of Euonymus were first reported here, and three subtypes of axile placentation were detected: (1) apical-axile, (2) basal-axile, and (3) dispersed-axile. This study highlights the importance of the floral features and provides better understanding of the relationships among sections in Euonymus.