Karyological studies on Gentiana section Cruciata Gaudin (Gentianaceae) from China

SUMMARYChromosome numbers and karyotype structures were determined for 12 populations of 6 species of Gentiana L. sect. Cruciata Gaudin from China. The basic chromosome number x = 13 was confirmed for all the taxa. G. straminea Maxim, is tetraploid (2n = 52); while G. crassicaulis Duthie ex Burkill, G. dahurica Fischer, G. fetissowii Regel et Winkler, G. macrophylla Pallas and G. officinalis H. Sm. are diploid (2n = 26). The chromosome numbers of G. crassicaulis and G. officinalis are reported here for the first time. The karyotypes of the species belong to the 1A and 2A types according to STEBBINS' asymmetry classification of karyotypes. The existing karyological studies on the genus Gentiana are concisely reviewed and the differentiation of species and its mechanisms are discussed.