Abstract: The Organic development sequence of Alisma orientale in early stage of ontogeny was studied. Two stages were divided:proembryo-mature seed embryo stage is characterized by the development of shoot apex being earlier than root apex, and plumular nodal root primodium, and being faster than radicle primodium; seed germination-seeding formation stage is characterized by the radicle growth being faster than plumular nodal root. And it was pointed out that the aquatic plants Euryale ferox and0 Nymphaea caerulea are of same characters as the former and the land plant Gentiana manshurica is of same characters as the latter.

Key words: Alisma orientale, Ontogeny, Organic development sequence