Chromosomes of Crassulaceae from Japan and South Korea

Abstract

Chromosome numbers are reported for 257 collections, representing all but about five of the approximately 35 species of Crassulaceae native to Japan and South Korea, 21 of them for the first time. These species differ considerably among themselves in their chromosomes: in number, in size, and in the constancy or variation within species. A higher proportion of triploids and other odd-ploids has been found than is known in the family elsewhere, usually accompanied by obvious adaptations for vegetative propagation. Several species or species complexes that vary greatly in their morphology have been found to vary also in their chromosomes; but not enough is known about them yet to propose new ways of classifying them. Rough measurements of nuclear volume support the conclusion that members of two species complexes differ in the types of chromosome change predominating in their evolution, polyploidy in S. Sect. Aizoon and structural chromosomal rearrangements in S. polytrichoides sensu latiore.