XVI International Botanical Congess

Comparative embryology 12 species in the genus Euphorbia L. were studied in the present work. The type of embryo sacs were found to be the Polygonum type, the Allium type, the Penaea type. It not only clarifies types of embryo sac of E. heterophylla and E. pulcherrima, but also compares and analyzes the different forms of the nucellar beak. According to the data from the present and previous works, the comparative embryological characters of 12 species in the genus Euphorbia L. were described. The results are shown that there are great similarities between subgenus in the genus Euphorbia, but there are differences in types of embryo sacs, forms of nucellar beak and presence of carumculate or not. The concept of the genus Euphorbia proposed by Webster (1967) were discussed with the comparison of embryological data. The present of embryological data substantiates the classification of the Euphorbia into five subgenus. Meanwhile, the systematic relationships between the subgenus of the genus were alsodiscussed. The trend from primitive to advance is Subgenus Esula, Subgenus Poinsettia, Subgenus Euphorbia, Subgenus Agaloma, Subgenus Chamaesyce.