Phenetic and cladistic analyses of Boraginaceae Juss.

Abstract

Abstract Background The systematics of family Boraginaceae draw attention of many botanists for many years. The current study's primary goals are to clarify phenetic and phylogenetic relationships within Boraginaceae according to morphology and molecular characteristics and to evaluate the morphological characters that can be applied in systematics of Boraginaceae. Results The macromorphological characters of 39 species, 2 subspecies and 5 varieties of wild boraginaceous plants were extracted and subjected to phenetic and principal component analysis that was performed for detecting the most important characters differentiating the studied taxa. The generated dendrogram is divided into five clear groups; Arnebia decumbens var. macrocalyx and Heliotropium curassavicum are the most distantly related species, while Echium angustifolium subsp. angustifolium and E. angustifolium subsp. sericeum are the most closely related species. The phylogenetic relations among the examined taxa were determined using DNA barcoding of the rbcl gene. The phylogenetic analysis generated a cladogram showing that among the studied taxa of Boraginaceae there is a bolster for three clear lineages with resolved relationships. Conclusions It is concluded that the chosen morphological characters were important in species delimitation, where more than half of the total morphological variations (67.94%) were explained by the first two principal components, indicating that the morphological characters showed high variability, which is useful for discrimination, and these characters, in addition to molecular characters, shared in drawing the phenetic and phylogenetic relationships within Boraginaceae that were considered not monophyletic groups. Boraginaceae contained some monophyletic genera such as Heliotropium and Alkanna, while the other studied taxa expressed a non-monophyletic relationships.