Cyto-genetical Studies in the Genus <i>Solanum</i>. I

Abstract

1. Among the plants generally termed as S. nigrum by the systematists the author found two types, karyologically distinct. One of them is n=12, and the other n=36.2. Close examination proved that both types are not exactly alike, differing in many points of their morphological characters. The type with 36 chromosomes is the typical S. nigrum, but, the other with 12 chromosomes deserves to receive a new specific name, S. photeinocarpum.3. S. nigrum is generally distributed throughout the northern part of Japan, whereas S. photeinocarpum occurs in the south. S. nigrum rarely found in Taiwan is of recent introduction, and its distribution is limited only to a few locales.4. The chromosome behavior observed in meiosis proved that S. photeinocarpum is a diploid form of the genus Solanum, while, S. nigrum is an autohexaploid.5. Size of the vegetative and reproductive organs of S. nigrum is markedly larger than that of S. photeinocarpum.6. The comparison of morphological characters and the survey of geographical distribution suggest that, there is an intimate relationship between both types with respect to the evolution of species.