pantoporate, but pores clustered around one pole; psilate to scabrate

zonoporate (4-5 pores), pores slightly elongated without vestibulum (otherwise very similar to Alnus); distinctly protruding annulus; psilate, dorso-ventrally flattened pollen grain

tri- or occasionally pantocolpate; columellae bordered by a white ring; tectum corrugated; scabrate