Juglans Pollen

Juglans (walnut tree) is small genus of deciduous trees widely known for the edible seeds. Three Juglans species occur in Oklahoma with J. nigra the most broadly distributed species. Juglans species are monoecious with male catkins and female flowers on the same tree. 

Pollen grains are periporate with multiple aspidate pores; however, pollen grains are also heterpolar with an uneven distribution of pores. Pores are found on the equator and one hemisphere of the grain. Pollen grain size is 36-45 µm. Juglans pollen typically occurs in the Tulsa atmosphere from mid-April through May.