Cytological studies of Rungia (Acanthaceae) from China and its systematic implications

In this study, the somatic chromosome numbers for 30 populations representing 14 Rungia species from China were investigated. Chromosome counts for eleven of these species are reported for the first time, excluding Rungia pectinata, R. hirpex and R. flaviflora. The genus presents rich cytological diversity, with chromosome numbers of 2n = 20, 22, 26, 28, 40, 42, 50, 52 and 56. Polyploidy is prevalent, occurring in ten populations representing six species and accounting for approximately 33% of the studied populations. Based on the integration of the present data with previous reports, five basic chromosome numbers (x = 10, 11, 13, 14 and 25) were identified for the 16 species with available data. This pattern of base numbers is largely congruent with some key morphological data, such as capsule type and anther size. These findings confirm the significance of chromosomal data in the systematic analysis of Rungia, particularly for infrageneric classification, while also highlighting the need for further molecular and micromorphological studies to draw more comprehensive conclusions.