There are three approaches to the problem of distinguishing the pollen of Betula nana. Grain morphology is not considered a reliable criterion. Size measurements alone serve to distinguish B. nana pollen from B. tortuosa, whilst the grain diameter: pore depth ratio distinguishes B. nana from B. pubescens. Reliable separation of B. nana pollen from tree birch pollen requires both these parameters.
If you can't find a tool you're looking for, please click the link at the top of the page to "Go to old article view". Alternatively, view our Knowledge Base articles for additional help. Your feedback is important to us, so please let us know if you have comments or ideas for improvement.