Fig. 2 A, B) Photomicrographs of pollen from Castanea sativa (European chestnut) in different views. This is the most abundant type of pollen type found in this sample of honey. C, D) Photomicrographs of pollen from Rhododendron species, in different views. The rhododendron pollen was responsible for the toxicity.

The scale under each photomicrograph represents 10 μm.