Cytogenetic studies on some species of euonymus

Abstract

A study of mitosis in root tips revealed E. atropurpúreas and E. kiautschovicus to have n = 16, while n = 32 was recorded for E.alalus and E.Fortunei forma coloratus. Karyotypic analysis could not be undertaken due to the smallness of the chromosomes and the lack of morphological detail. Two different chromosome numbers were observed in the collective taxon E. Fortunei.Microsporogenesis was found to be highly regular in E. atropurpúreas and E. kiautschovicus, with the exception of irregular quartet formation in 5% of the microsporocytes of the latter species.E. americanus and E. alatus appear to be segmental allopolyploids. Weak asynapsis was evident in these two tetraploid species. Precocious chromosome movement at anaphase II occurred in E. americanus.The genus Euonymus may reveal interesting relationships from the aspects of hybridization, polyploidy, and apomixis. © 1972 Taylor & Francis Group, LLC.