Key to the Quaternary pollen and spores of the Great Lakes region /

Key to Pollen Classes A. Grains in groups of 4 1 Tetrads p. AA.Grain single (monads) B. Apertures absent (or indistinct) C. With two bladders 2 Vesiculate p. CC.Without bladders D. With ridges separated by folds 3 Polyplicate p. DD.Without ridges and folds 4 Inaperturate p. BB.Apertures present E. Apertures simple, i.e. either pores or colpi F. With pores 1 pore 5 Monoporate p. 2 pores 6 Diporate p. 3 pores 7 Triporate p.More than 3 pores equatorially arranged 8 Stephanoporate p.More than 3 pores, some or all not equatorial 9 Periporate p. 7 FF.With colpi 1 colpus 10 Monocolpate p. 2 colpi 11 Dicolpate p. 3 meridional colpi 12 Tricolpate p.More than 3 meridional colpi 13 Stephanocolpate p.More than 3 colpi, some or all not meridional 14 Pericolpate p. 1 EE.Apertures compound, i.e. pores in colpi 3 colpi meridionally arranged 15 Tricolporate p. 1 More than 3 colpi meridionally arranged 16 Stephanocolporate p. Key to Spore Classes A. Spore without aperture 1 Alete p. AA.Spore with slit-shaped aperture (laesura) B. Spore with single laesura 2 Monolete p. BB.Spore with triradiate laesurae 3 Trilete p. Key to Pollen Grains 1. Tetrads F. With colpus membrane, endexine thin.Rare.Rosaceae Dryas 9g-i FF.Colpus membrane absent, endexine thick.Rare.Acer- aceae Acer negundo 9j-l BB.Reticulate G. Colpus with psilate-scabrate margin, polar area small