Structure and Diversity of the Woody Conifer Seedling-Like Structures from the Upper Cretaceous of Hokkaido, Japan

Abstract

Permineralized conifer seedling-like structures have been found in calcium carbonate nodules from the Middle and Upper Yezo Groups (Upper Cretaceous) of Hokkaido. Four types of seedlings have been identified, including those with nests of sclerenchyma in a parenchymatous pith and large amounts of secondary xylem; those with parenchymatous pith and resin canals in the primary xylem with traumatic resin canals in the secondary xylem; and intermediate forms with parenchymatous pith lacking resin canals in the primary xylem but sometimes having them in the secondary xylem; or those completely lacking resin canals. These fossils are compared to the fossil seedling-like structures from the Cerro Cuadrado petrified forest of Patagonia that they resemble to a large extent. Some of these specimens and those from Cerro Cuadrado most closely resemble those produced by abnormal seedling growth in the extant Araucaria, section Bunya. Several of them, however, may have been produced by different conifer families or may...