Molecular phylogeny of Brachycome (Asteraceae).

Intrageneric relationships in the genus Brachycome were investigated by the comparison of nucleotide sequences of the chloroplast gene matK. Evolutionary trends of some morphological and cytological characters were estimated based on the matK tree. The results indicate that Brachycome is divided into four major clades, and circumscription of superspecies based primarily on fruit morphology is not fully supported. Fruit morphology has evolved in parallel from simple to complex structures in several lineages. The ancestral basic chromosome number is x = 9, and lower chromosome numbers are the products of several dysploid reductions from n = 9 in two of four major clades of Brachycome. [ABSTRACT FROM AUTHOR]