Abstract: 【Objective】The pollen morphological characteristics of different Medicago varieties were compared in order to provide basis for studying Medicago variety evolution.【Methods】The pollen size,shape,germination pore groove,and surface decoration of seven Medicago varieties were compared using a Hitachi S-530 scanning electron microscope.【Results】Medicago Sativa L. cv. Aohan had the longest polar axis（44.27 μm）,whereas Medicago ruthenica L. Sojak cv. Zhilixing had the shortest（35.48 μm）. The equatorial axis of Medicago Sativa L. cv. Caoyuan No. 4 was the longest（26.39 μm）,while the equatorial axis of Medicago ruthenica L. Sojak cv. Zhilixing was the shortest（20.56 μm）. The seven Medicago varieties had polar axis length to equatorial axis length ratio（P/E）of 1.54 to 1.81. The largest was Medicago Varia Martin cv. Caoyuan No.1,while the smallest was Medicago Sativa L. cv. Caoyuan No. 4. Seven Medicago varieties had pollen diameters ranging from 26.99 to 33.71 μm. Among them,Medicago Sativa L. cv. Aohan was the largest,whereas Medicago ruthenica L. Sojak cv. Zhilixing was the smallest.【Conclusion】 Pollen from the seven Medicago varieties are all medium in size,long spherical,trifid circular in polar view and oval in equatorial view,with 3-hole grooves and cave-like or shallow cave-like surface decoration.

Key words: Medicago, Pollen morphology, Pollen germination holes, Pollen surface decoration