Abstract: By using genetic analysis to 5 main morphological characters of frist filial generation from posititively or negatively crossed combinations of Azolla microphylla?A.filiculoides(B譇)and A.mexicana?A.filiculoides(M譇).some of important hereditary features Of F1 generation from interspecific hybridization in Euazolla were revealled, and it provided a basis Of plant morphology and reproductive biology for the identification to hybrid seedlings.These 5 characters include:leaf colour; tricomes on dorsal lobes; glochidia of massulae:sporocarp fertility:and stem bifurcation and plant morphology.Except that the leaf colour and bifurcation of B譇 and M譇 combinations are as same as parent plants, other four hereditary features are different from the parents.In addition.some abortion mechanism of microsporocarp from hybrid progenies and the effect of its fertility on Euazolla taxonomy were preliminarily analysed.