Radial immunodiffusion, rocket immunoelectrophoresis, and Boyden procedure have been employed as quantitative analysis of pollen proteins in a systematic investigation of selected amentiferous plant taxa. Data presented here are continued and supplementary to the previous qualitative analysis of immunoprecipitin systems for the same purpose. Although the number of taxa tested has been limited, the serological evidence indicates that the Betulaceae has the greatest simnilarity to the Fagaceae, next to the Juglandaceae, the least to the Salicaceae, when antisera against Alnus hirsuta and Betula platyphylla var. japonica were used for tests. Within the Betulaceae Alnus and Betula show greatly similar affinities together, but less similar to the rest of genera: Carpinus, Carya and Corylus. When antisera against Quercus aliena, Q. dentata, and Q. glauca were used for tests, the following decreasing order of serological affinities was obtained: Quercus→Alnus, Betula→Carpinus, Carya, Corylus→Juglans, Pterocarya→Populus. Overall serological data comne closer to supporting the classification systems of Cronquist, Takhtaja, and Hutchinson; but less of Thorne and Bessey. In addition this investigation indicated that pollen, with its high protein content, provided an excellent source of extractable antigens for serosystematic researches.