The other problem with pollen identifier books is that they are region-
specific and ecotone-specific.  If you're in England, you're getting very
different pollen loads from the eastern United States from the Southwestern
United States, from Greece, from...   Also, if you're in proximity to a
specific crop, or (like many hobbiests) around a suburban planting environment,
it's going to have a big effect that may not be reflected in superficial
appearances of what's in the pollen baskets at a specific time.  Unless you're
willing to put the pollen under a microscope and examine morphology, you
would be better to just observe the pollen loads on the bees on flowers, as
mentioned.
 
Jane B. [[log in to unmask]]
(in San Jose, California, of the strange current climate)