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The Icacinaceae occur pantropically today, but are well represented by fossil fruits of the warm Early Middle Eocene, when tropical plants that currently occupy low latitudes were more widely distributed in higher latitudes. Members of this family are first known in the Late Cretaceous; however, fossil fruits of tribe Iodeae are quite rare before the Eocene. In this paper we describe the first formally recognized Late Paleocene icacinaceous taxa from western North America. We name two new species of Icacinicarya based on anatomically preserved fruits and establish a new genus, Icacinicaryifes, for impressions with a strong similarity to icacinicarya that lack anatomical preservation. These new records from the Almont/Beicegel Creek flora in North Dakota and several localities in Wyoming, Colorado, and Montana complement records known from the Early Eocene of England and document an increased diversity of Iodeae and related forms in the Paleogene of western North America. [ABSTRACT FROM AUTHOR]

Susiea newsalemae Taylor, DeVore & Pigg gen. et sp. nov. is described for distinctive seeds referable to the water lily family Nymphaeaceae from the Late Paleocene Almont Flora of central North Dakota, U.S.A. Seeds are oval to barrel shaped, 5 mm long × 3 mm wide, and have an apical operculum and a prominent lateral raphe. The outer surface of the seeds is composed of palisade, shinglelike cells 40 µm high × 150 µm wide with smooth cell margins lacking papillae. The operculum is 1 mm across and surrounded by a narrow furrow, covering the micropyle but not the hilum. The raphe and micropyle are separated by several cells. Several specimens have a small embryo cavity surrounded by a small area of presumed endosperm below the micropyle and a well-developed perisperm filling the rest of the seed cavity. Susiea seeds are most similar to those of extant Euryale but differ in features of the epidermal cells, seed coat, and raphe morphology. They also share some features with Nymphaea, Nuphar, and Victoria. Susiea appears distinct from the permineralized fossil seeds of the middle Eocene Allenbya from the Princeton chert, Nuphar wutuensis from the Eocene of China, and Nuphar cf. wutuensis from the same Almont beds. Susiea is the oldest fossil taxon of the Euryale lineage, extending the previous Oligocene record back to the Late Paleocene and documenting a significantly older age for the Euryale/Victoria clade that is clearly a derived lineage based on phylogenetic analyses of modern taxa. [ABSTRACT FROM AUTHOR]

A developmental and anatomical study of the staminate flowers of Halophytum ameghinoi showed decussate tepal estivation; residual growth of the receptacle after stamen inception; monocotyledonous and basic types of anther wall development; secretory, binucleate tapetal cells; tetrahedral tetrads; and binucleate pollen grains. A vacuolate stage in the archesporial cells, the structure of endothecial thickenings, and a mechanism of anther dehiscence by connective contraction are new autapomorphies for this family. Anemophily is confirmed (Plantago-type syndrome), and field studies of pollen release showed a subtle mechanism involving rigid anther wall structure, versatile anther insertion, and abaxial subterminal pores. In air currents, while anthers flutter with pores directed upwind, pollen is extracted presumably by a cavitation effect of the hooded anther tip. In a phylogenetic context, anemophily of Halophytum is of isolated occurrence within Caryophyllales, and uniovulate ovaries in sister clades probably represent a prerequisite for evolution of anemophily. [ABSTRACT FROM AUTHOR]