Agmatoploidy inCarex laevigata (Cyperaceae). Fusion and fission of chromosomes as the mechanism of cytogenetic evolution in Iberian populations

In this paper cytogenetic studies on 64 specimens from 20 Iberian populations ofCarex laevigata (Cyperaceae) are presented. Chromosome behaviour in meiosis suggests that the different chromosome numbers obtained (ranging from 2n = 69 to 2n = 80) were distributed according to an increasing geographic gradient of chromosome fission along the North South direction. Four relatively stable areas were also delimited according to chromosome numbers displayed by this species, i.e. 2n = c. 72, c. 74, c. 76, and 78. The meiotic behaviour ofCarex ×deserta (C. laevigata ×C. binervis) was also studied.