Guelder rose, Viburnum opulus Family: Adoxaceae Pollen grain morphology: spheroidal, tricolpate, reticulate Pollen grain size: 22.77 + 1.75 µm by 20.25 + 0.10 µm April 29, 2015Adoxaceae, UncategorizedAdoxaceae, european cranberry, guelder rose, opulus, reticulate, snowball tree, spheroidal, tricolpate, viburnum