Numerical re-assessment of the phenetic relationship between Apocynaceae and Asclepiadaceae

Recognition of the Apocynaceae and Asclepiadaceae as one family or as two separate but related families with five subfamilies was for long highly controversial. Raising some of the subfamilies to the rank of family was also disbutable. To resolve this issue, 55 morphological and palynological characters were recorded in a data matrix comprising a sample of 41 species belonging to 24 genera of Apocynaceae and 75 species from 31 genera of the Asclepiadaceae. The data matrix was subjected to cluster analysis using the Sorensen’smeasure of dissimilarity and Ward's method of clustering in the PC-ORD version 5. Out of three possible interpretations of the result, we opted for that which suggestd considering the five subfamilies Apocynaceae-Rauwolfioideae, Apocynaceae-Apocynoideae, Asclepiadaceae-Asclepiadoideae, Asclepiadaceae-Periplocoideae and Asclepiadaceae-Secamonoideae as five distinct, neatly defined and homogeneous