Abstract: This paper studied the differentiation and the regularitics of distribution of megasporophyll and microsporophyll cones of Zhangbai larix (Larix olgensis Henry). Results were:(1) in the last ten days of June, the period of bud scale formation ended, the period of differentiation or microsporophyll began at the beginning of July and ended between the end of July and the early of August. In the first ten days of August, the ment entered into the period of microsporagia formation, sporogenous cells appeared in the last ten days of August and microsporocytes were formed in the middle ten days of September. At the end of October, microsporocytes remained in the stage of Leptotene and then went into winter dormancy. (2) At the beginning of September, bract primordia initiated to form, In the middle ten days of September, primordia of ovule scales formed, in the first ten days of October primary ovules appeared, in the last ten days of October, megasporocytcs were formed, and at the end of October megasporophyll cone buds went into winter dormancy. (3) Microsporophyll cone buds mainly distributed in the middle and lower regions of the crown and greatly exceed megesporophyll cone buds in number, at about 19 folds. Megasporophyll cone buds mainly concentrated in the middle region of the crown, while number of budsin the lower region were greater than that in the upper.

Key words: Larix oigensis, Male cone flower bud, Female cone flower bud, Differentiation