Supposedly Colpate Pollen Grains from the Jurassic

Abstract

Some Mesozoic spores and pollen grains claimed in a recent publication to exhibit angiosperm-like features are discussed. It is suggested that Poroplanites Pflug, is actually a trilete fern spore. The “ germinal apparatus ” of the Poroplanites type is simply an optical section of the characteristic folding of a lobe of a trilete spore, flattened along the polar axis and seen in equatorial view. It is shown that Pflug's Poroplanites type can be reproduced almost exactly in the trilete spores of a living tree fern. Classopollis Pflug, Circumpollis Pflug, and Canalopollis Pflug are pollen grains with distinct annular thickening, similar to the pollen grains of the Jurassic araucarian, Pagiophyllum connivens Kendall.