In May, the ancient woodlands in England and across northwest Europe can have a lilac-blue haze that hovers at shin-level. The cause of this iridescence is the flowering bluebells. While they may be striking to see, they are largely absent from the pollen-record of past environments. This is partly due to where samples are taken from (rarely from ancient woodland sites) and also due to the fact that bluebells are insect pollinated, and therefore the pollen does not travel very far from it's source.
The pollen grains of the native bluebell (Hyacinthoides non-scripta) are large, often between 50-100 µm and folded, like the grain above.