• Korean Journal of Plant Resources
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• v.33 no.2
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• pp.116-129
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• 2020

The genus Sedum comprises about 400 taxa with worldwide distribution, and about 20 taxa of the genus Phedimus distributed from Asia to Europe. According to some taxonomists, Phedimus and Sedum are two separate genera of the family Crassulaceae; however, in Korea Phedimus has been treated as a subgenus Aizoon within the genus Sedum. This ambiguous taxonomic treatment of the genus Phedimus needs further confirmation. In the study, we investigated morphological characteristics such as the whole plant height, leaf morphology, and seed coat features of these two genera. We believe that these characters are very important to distinguish Phedimus and Sedum. The result indicated that the seed surface pattern was the most useful diagnostic character. The Sedum had a hexagonal pattern with a single nipple protrusion, whereas the Phedimus had a rectangular pattern with papilla on both ends. The results of this study strongly support the separation of Phedimus from Sedum and thus Phedimus need to be treated as an independent genus.