Taxonomic evaluations on the anatomical characters of leaf and achene in Turkish Tripleurospermum with its relative Matricaria (Asteraceae)

Abstract

Tripleurospermum is a typically Mediterranean genus with ca. 40 species. It is widespread and diverse in Turkey with ca. 32 taxa, of which 12 are provided anatomical traits of both leaf and achene/cypsela, previously. In addition, the leaf anatomy of endemic T. baytopianum as well as the achene anatomy of endemic T. rosellum var. album with diploid cytotype are presented from Turkey. In this study, the anatomy of both leaf and achene of 15 taxa as well as achene anatomy of T. baytopianum and T. rosellum var. album with tetraploid cytotype were described in detail from Turkey. The leaf and achene anatomical characteristics of Turkish Tripleurospermum and its closely related genus Matricaria using multivariate analyses (cluster analysis, principal components analysis) were evaluated in taxonomic context. Additional data of further species of Tripleurospermum as well as Matricaria (four taxa) were taken from the literature for multivariate analyses. All studied taxa have the basic leaf structure with lower and upper epidermis including anomocytic stomata, parenchymatic mesophyll, and vascular bundle. The pericarp is composed of several layers of parenchymatous and sclerenchymatous cells with one vascular bundle in each rib. The thickness of palisade sclerenchyma in the pericarp, the vascular bundle length in the midrib of the leaf, and presence or absence of a slime envelope have high taxonomic value at interspecific/intergeneric levels.