Frequency and Abundance of Pollen Taxa in Crime Case Samples from the United Kingdom

The frequency and abundance of pollen taxa in samples from crime cases in which forensic palynology had been employed,
was investigated by collating pre-existing data. Fifteen cases from England and Northern Ireland that represented a range of habitats and exhibit types were selected and a total of 199 samples were included in the analysis. Control samples were considered separately to those from exhibits. The latter contained a wider range of taxa and were more likely to contain pollen from planted ornamentals such as Cedrus, Ligustrum, Juglans and Platanus. Pollen of the Poaceae family occurred in 100% of samples and in the greatest mean abundance (25.65%) and the wind-pollinated taxa of Pinus, Betula, Quercus, Alnus, Fraxinus, Corylus and Urticaceae also occurred with very high frequency (> 80%). Most taxa had a mean abundance of < 6% but several were higher. Maximum abundance was also studied, varying greatly from the mean in some taxa, notably Castanea sativa, Plantago lanceolata-type, Pteridium aquilinum and Quercus. Not all taxa that occurred frequently were wind-pollinated: some members of the insect-pollinated families of the Apiaceae, Asteraceae, Brassicaceae, Ericaceae and Rosaceae, as well as Hedera helix and Sambucus, were quite frequently found, sometimes in relatively high maximum abundance. The results demonstrate that pollen from certain plants repeatedly occur in both control and exhibit samples. This information can assist with the evaluation of pollen profiles in crime cases.