Corylus avellana - Hazel
A small multistemmed tree. Flowers early spring. Male flowers are catkins, very profuse pollen; female flowers are small, red, and insignificant, on a swollen green bulb.
Pollen grains are distinctive rounded triangular. When fresh the internal cytoplasm forms distinct arcs. Three large and clear pores, one on each apex of the triangle. About 25 microns across.
