Fig. 2.

Start date of the main pollen season at London, ON, for the taxa: Cupressaceae (brown), Acer (green), Populus (blue), Quercus (purple), Morus (red), Poaceae (pink), and Ambrosia (orange). Open circles indicate unreliable start dates (calculated start dates that occur within 7 sampled days of the first sampling date). Filled circles indicate reliable start dates. Grayed out areas are dates at which pollen was not sampled