UPPER CRETACEOUS ARAUCARIAN CONES FROM HOKKAIDO AND SAGHALIEN - ARAUCARIA-NIPPONENSIS SP-NOV

Six ovulate, permineralized cones, four cone-scale complexes, and one isolated seed are described from the Upper Cretaceous Upper Yezo and M iho Groups from Hokkaido, Japan, and Saghalien, Russia. Cones are sphe rical, 3.5-6.0 cm in diameter, with prominent thick bracts. Thick ovul iferous scales are almost completely united with the bracts and are no t readily distinguishable on all scales. Cone-scale tissues consist of prominent abaxial and adaxial sclerenchyma bands with a central zone of thin-walled cells filled with dark contents that are often missing in abraded cones. Cone-scale vasculature is located in the chin-walled cells of this central zone. There is one large ovule per cone-scale c omplex with a thick sclerotesta showing a zigzag sclereid pattern. The nucellus is free from the integument except at the chalaza and shows a prominent wavy apex. Megagametophytes and embryos with two cotyledon s are poorly preserved but are present in a few seeds. The presence of pollen tubes in the nucellar tissues of a fossil araucarian is demons trated for the first time in these cones. Cones can be distinguished f rom those of Araucaria nihongii by a larger overall size at maturity, the structure of the cone-scale and its tissue composition, the lack o f a bract abscission layer, and a thicker ovuliferous scale without a prominent ''Ligular sulcus.'' These cones show similarities to the Sou th American section Araucaria (= Columbea) species and are known to ha ve shed their scales at maturity.