Morus Pollen

Morus (mulberry) is a genus of trees widely distributed in subtropical and temperate areas of the world. Three species of mulberry are found in Oklahoma, Morus rubra (red mulberry), M. alba (white mulberry), and M. microphylla (Texas mulberry). Two of these species (red mulberry and Texas mulberry) are native to Oklahoma, while white mulberry was introduced and has become naturalized. Mulberries are dioecious species with separate male and female trees. 

The pollen grains are small (16-22 µm) and generally have two pores (occasionally three) with a prominent oncus beneath each pore. Morus pollen release generally begins in mid-March, peaks in early April, and gradually decreases through early May.