Abstract

PREMISE OF THE STUDY: Nearly 200 araceous leaves and two spadices have been identified among Paleocene fossils from the Blindman River locality near Blackfalds, Alberta, Canada. Although not found in attachment, these probably represent parts of the same plant.
METHODS: Specimens were studied using light microscopy. Phylogenetic analyses using a modified morphological matrix of living and fossil Araceae were performed using TNT version 1.5 to help establish the relationships of the fossil leaves and spadices within Araceae and to each other.
KEY RESULTS: Leaves are simple with a broad petiole and entire-margined, elliptic to ovate or oblong blade with an acute to slightly rounded apex. A multi-veined midrib extends into the basal region of the blade, from which parallelodromous primary veins of two orders diverge at acute angles, converging with a submarginal vein or at the apex. Transverse veins are opposite percurrent, producing rectangular to polygonal areoles with mixed opposite/alternate higher-order veins. Spadices are cylindric, with helically arranged, bisexual, perigonate flowers, each with six free tepals and a protruding style. Fruits are trilocular, with axile placentation and one seed per locule.
CONCLUSIONS: Leaves are assignable to the fossil genus Orontiophyllum J. Kvaček & S. Y. Smith as O. grandifolium comb. nov. Spadices are described as Bognerospadix speirsiae gen. et sp. nov. Leaves and spadices each conform to an early-diverging lineage of Araceae, increasing the known diversity of Proto-Araceae. Together, they provide strong evidence for extinct Proto-Araceae with novel combinations of characters shortly after the Cretaceous-Paleogene floral transition, increasing our understanding of aroid evolution.