Distribution, paleoecology, paleoclimatology, and botanical affinity of the Eocene pollen genusDiporoconian. gen.

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Abstract
Diporoconia n. gen. is proposed for diporate subisopolar smooth to perforate pollen grains having annuli or tumescence. Diporoconia iszkaszentgyoergyi (Kedves) n. comb. (the type species), D. nnewiensis (Jan du Chêne et al.) n. comb., and D. spp. 1 and 2 are included in the genus. Distinctive characters of the pollen are the large pores that are at the ends of the grain but appear offset toward one face (interpreted to be the proximal face) and the greater convexity of the distal face than the proximal face, both features that indicate curving or arching of the equatorial axis that extends from pore to pore. Diporoconia is known from Hungary, France, England, Nigeria, Alabama, California, and Alaska. It is probably confined to the Eocene. Plants producing Diporoconia pollen probably lived in coastal environments in which the soil water was brackish or even marine. Statistical analyses of British assemblages containing this pollen indicate that it may have been produced by herbs or low shrubs. The climatic affinity of the genus is paratropical to tropical. Previous authors have suggested that Diporoconia pollen has affinities with Daemonorops (Palmae) or Alyxia (Apocynaceae). In this paper we examine modern pollen of these two genera in detail and conclude that the fossils do not belong to either genus; transmission electron micrographs are critical for these comparisons. However, several lines of morphological evidence indicate that the fossil grains are monocotyledonous.