Reconsideration of two infraspecific taxa of the fullmoon maple,Acer japonicum (Aceraceae)

Comparison of several critical morphological characters inAcer japonicum microphyllum Siesmayer andA. shirasawanum Koidzumi, show that the two taxa are identical; the former is synonymous withA. shirasawanum. Similarly, morphological data, supported by the chemical dichotomy of flavonols vs. glycoflavones withinAcer sectionPalmata, indicate thatA. japonicum aureum Siesmayer is in fact a form ofA. shirasawanum. The combinationAcer shirasawanum formaaureum (Siesmayer) Delendick is proposed for the golden fullmoon maple.