2012 Volume 62 Issue 2_3 Pages 61-68
Asarum celsum (Aristolochiaceae, section Heterotropd) and its allies were investigated on Amami-oshima, southwestern Kyushu, Japan. The results of morphological studies showed that three taxa, A. celsum, A. tabatanum, sp. nov., and A. nazeanum, sp. nov., with distinct morphological features and separate geographical ranges could be recognized. Asarum tabatanum is characterized by a larger globular-tubiform calyx tube, the inner surface of which is a complicated network of 19 to 24 longitudinal ridges and inter-connecting transverse ridges, and by longer stylar protuberances. Asarum nazeanum is distinguished from A. celsum and A. tabatanum by its large calyx tube spreading apically, sharp and prominent longitudinal and transverse ridges, and wider calyx tube entrance.