Article: Devonian megaspores from Arctic Canada
A megaspore assemblage is described from coal and shale deposits of Upper Devonian age from Ellesmere Island, Arctic Canada. All are new species, and two represent new genera: Biharisporites ellesmerensis sp. nov., B. ocksensis sp. nov., Triangulatisporites rootsii sp. nov., Lagenicula devonica sp. nov., Ocksisporites maclarenii gen. et sp. nov., and Nikitinsporites canadensis gen. et sp. nov. All but one of these forms are appre-ciably smaller than typical Carboniferous megaspores. There appears to be a general rise in the mean size of megaspores from the Devonian to the Carboniferous, followed by a diminution in size through the Mesozoic. This may be correlated with the corresponding rise and decline of the arborescent lycopods.