Generic Segregation of Some Sections and Subsections of the Genus Hydrangea (Hydrangeaceae)

摘要

De Smet (2015) united all genera classified Hydrangeeae by Engler (1930) into a single genus Hydrangea. These genera delimited by Engler are easily distinguished by their morphological features, and also their habitat and ecological preferences. To rescue the genera adopted by Engler we propose generic segregation of most of the sections and subsections of Hydrangea by Engler according to the tree by De Smet et al.(2015). Genus Hortensia Comm. ex A. L. Juss. applies to the species of sect. Euhydrangea subsect. Petalanthae of Engler, and is divided into three sections named Hortensia^ Chinemes, and Hirtae. Hydrangea involucrata and H. sikokiana are classified into genus Platycrater Siebold & Zucc-， Hydrangea integrifolia Hayata is transfered to genus Cornidia Ruiz & Pav" H. petiolaris Siebold & Zucにto genus Calyptranthe (Maxim.) H. Ohba & S. Akiyama, and also H. paniculata and similar species to genus HeteromaJla (Rehder) H. Ohba & S. Akiyama. The necessary combinations and new states are proposed. A new form of Hortensia serrata, named f. plenidecuris is proposed.