Tolong jelaskan mengenai Subdivisi dari Rhododendron

Wilson EH, Rehder A. A MONOGRAPH OF AZALEAS RHODODENDRON SUBGENUS ANTHODENDRON. THE UNIVERSITY PRESS, CAMBRIDGE April 15 1921. PUBLICATIONS OF THE ARNOLD ARBORETUM, No. 9

John L. Creech. An Embryological Study in the Rhododendron Subgenus Anthodendron Endl. Botanical Gazette Vol. 116, No. 3 (Mar., 1955), pp. 234-243