Abstract: Caladium is a notable ornamental foliage plant with beautiful and colourful leaves. It is of a tremendous number of horticultural varieties, thus resulting in some confusion of identification and nomenclature.Esterase isozymic patterns of roots of 13 caladium varieties were detected by using the technique of polyacrylamide gel electrophoresis on the vertical slabs.The results of the study showed that the bands observed in gels were grouped, according to their different migrants, into three regions, that is, Ea,Eb and Ec. The zymograms between varieties had no significant differences at the regions Eb and EC. The more anodal region Ea was apparently variable.On the basis of the zymogramatic patterns, all varieties of Caladium nortulanum Birdsey tested may be classified into three groups. C. bicolor Veat was also variable at Ea, where a band of faster mobility(Ea5)appeared.In the light of biochemistry the relationships were discussed between zymogram patterns and blade shapes,between the unstability of zymogram and the variability of morphology, thus providing scientific basis for expounding the characteristic features and classifications of caladium.