The Jurassic flora of Andøya, northern Norway

Abstract

The Jurassic flora from Andøya, northern Norway, is described based on bulk maceration of leaf-bearing material and reexamination of all available specimens described earlier; in addition, palynology is used for biostratigraphic and floristic evaluation. Three new species are described: Nilssoniopteris norvegicus n. sp., Ginkgo dahllii n. sp. and the leafy conifer stem Ramsaia ednyana n. gen., n. sp. In connection with Ramsaia, the status of the genera Allocladus Townrow and Cyparissidium Heer is discussed and it is concluded that both should be reserved for impression fossils. Previously described species of Allocladus based on cuticles have been transferred to Ramsaia. Two floras are comprised in the material, which are of Middle Jurassic (probably Bajocian) and Late Jurassic (Kimmeridgian) age, respectively. The older and better known is dominated by the "Sciadopitys-like" conifer leaves Oswaldheeria macrophylla (Florin) Bose et Manum, followed by ginkgoalean leaves (Ginkgo, Pseudotorellia), while bennettites and other conifers are rare and cycads appear to be missing. This composition differs from Middle Jurassic floras of lower palaeolatitudes, suggesting the existence of a boreal phytogeographic province in Middle Jurassic times. The younger flora is known only from casual specimens of poorly documented stratigraphic provenance, the most significant components being two species of Mirovia, conifer leaves with Sciadopitys-like stomatal distribution.