The floral vasculature in the three related genera, Diphylleia, Podophyllum and Dysosma, was investigated. In all three genera, the stele in the peduncle and pedicel is composed of 2(-3) circles, or systems, of vascular bundles, with the exception of Diphylleia cymosa where the pedicellate stele consists of a single circle of vascular bundles. Similar receptacular vasculature is observed in the three genera ; more complicated in Podophyllum, less complicated in Dysosma and simple in Diphylleia. The outer sepals receive traces mainly from the outer vascular system, and the inner sepals receive traces from both the inner and outer systems. The basic trace pattern of the petal and stamen traces is double in nature. A specialized condition of the stamen traces is observed in the two species of Podophyllum, and the trace pattern is considered to be derived from a trace pattern of a double nature. Regular division and fusion are not observed in the receptacular stele. The pistillate vasculature in these three genera is also similar. The pistils are traversed by a few ventral, a dorsal and some lateral bundles. These bundles extend to the stigmatic region. In the placenta of Podophyllum and Dysosma, a placental vascular network system is observed. The ovary wall is covered by venation forming a large network. The evidence from floral vascular anatomy supports the concept that these three genera constitute a separate natural taxon in the Berberidaceae. I am indebted to Prof. K. IWATSUKI of Kyoto University for his valuable advice and to Dr. KATO for his instructive criticism. My thanks are also due to the curators of the Botanical Gardens in Zurich, Switzerland, Milano, Italy, Berlin-Dahlem, West Germany, and Koishikawa, Tokyo, and to Dr. T. HASHIMOTO of Toyama University, Mr. M. ITO of Kyoto University, Dr. WAN JIZXIANG and Mr. H. WATANABE for giving me materials used in this study. In addition, I appreciate the kindness of Dr. DAVID E. BOUFFORD who also gave me materials and read the manuscript.
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