Chromosome numbers were determined in 23 accessions representing 21 species hitherto belonging to Chirita (Gesneriaceae), a genus that has recently been remodelled and split into five different genera: Damrongia, Henckelia, Liebigia, Microchirita and Primulina. The previously monotypic Primulina tabacum was also investigated. Counts for 19 species were new, two were confirmatory and two gave different numbers from previously published counts. The results here, together with previously published cytological data for the erstwhile genus Chirita, were analysed in the light of the taxonomic revision of the genus and published phylogenetic data. Chirita was originally highly heterogeneous in chromosome numbers, including seven different somatic numbers, 2n = 8, 18, 20, 28, 32, 34 and 36. Among the five remodelled genera, Henckelia was found to be as equally heterogeneous as the erstwhile Chirita, Microchirita included only two chromosome numbers, 2n = 18 and 34, the three species of Damrongia were uniform with 2n = 18, while species belonging to the extended Primulina showed only one basic number, x = 18, with 15 samples being diploid, and one being tetraploid. In the light of recent phylogenetic studies, polyploid as well as dysploid changes appear to have shaped the genomes of the newly defined genera Henckelia, Microchirita and, to a lesser degree, Primulina.

Our knowledge of cytological data published on members of the family Gesneriaceae is summarized and critically evaluated in the light of current taxonomic treatments and phylogenetic hypotheses. There are about 1000 published chromosome counts, covering 56% of the genera but only 18% of the species. In particular the New World tribes Beslerieae and Napeantheae and the Old World tribe Didymocarpeae are underexplored at generic level. In Gesneriaceae chromosome data are a valuable source of taxonomic characters. From our current knowledge of the phylogenetic relationships in the family we know that basic chromosome numbers in the New World subfamily Gesnerioideae appear to be rather conserved, but that a more complex pattern of genome evolution seems to be present among the Old World tribes. Both polyploidy and dysploid changes have played a significant role in the evolution of the family. However, the number of species for which both cytological and molecular data are available is at present too low to reach firm conclusions on ancestral basic chromosome numbers, particularly for the Old World group. To facilitate wider access to cytological data on the Gesneriaceae, a website has been developed (http://www.rbge.org.uk/rbge/web/search/index.jsp), which is introduced in this paper.