AN UNEXPECTED EQUISETUM (EQUISETACEAE) TAXON NEW TO THE EUROPEAN FLORA

摘要

A new diploid nothosubspecies of Equisetum xmoorei is described from a limestone quarry in Germany as the cross between the alien E. hyemale subsp. affine and E. ramosissimum. Its diagnostic features are listed in detail and compared with those of native European E. xmoorei, the parent taxa of both, and the somewhat similar triploid E. xgeissertii. Plants close in morphology to the new taxon are found in Japan, where both parent species co-occur naturally. The name of the new nothosubspecies refers to this fact and hence a type specimen from Japan is selected.