Search for the wild ancestor of buckwheat II. Taxonomy of Fagopyrum (Polygonaceae) species based on morphology, isozymes and cpDNA variability.

Four newly discovered and seven previously known Fagopyrum species were classified based on their morphology, isozyme variability, and RFLP of chloroplast DNA (cpDNA). Three independently constructed phylogenetic trees showed good agreement and we had sufficient confidence in them to assert that they probably reflect the phylogenetic relationships among the Fagopyrum species. The new classification differs from Steward (1930)'s classification in the position of Fagopyrum tataricum and F. gracilipes; F. tataricum is very close to F. cymosum. The new classification resolved several problems which we suffered from, when we used Steward's classifiction. Three new species, F. pleioramosum, F. callianthum and F. capillatum are closely related to F. gracilipes. New species F. homotropicum is very close to F. esculentum in morphology as well as in isozyme variability.