Cones, seeds, and foliage of Tetraclinis salicornioides (Cupressaceae) from the Oligocene and Miocene of western North America: A geographic extension of the European Tertiary species

The cupressaceous genus Tetraclinis is recognized from the Oligocene and Mi ocene of western North America on the basis of co-occurring seed cones, see ds, and foliage branches. Morphological and anatomical comparisons with the two previously recognized European Tertiary species indicate that the Nort h American specimens are morphologically inseparable from Tetraclinis salic ornioides (Unger) Kvacek. The North American taxon is treated as a new vari ety, T. salicornioides (Unger) Kvacek var. praedecurrens (Knowlton) comb, e t stat. nov., and is distinguished from the European representatives, T. sa licornioides (Unger) Kvacek var. salicornioides, by slight anatomical diffe rences in the leaf epidermis. Although cones and seeds of the fossil specie s are closely similar to those of extant Tetraclinis articulata, the foliag e is more "spreading," composed of flattened segments with fused facial and lateral leaves that are apparently adaptive for a more mesic climate. The recognition of T. salicornioides in western North America along with the ab sence of Tetraclinis in the fossil and recent flora of eastern Asia provide evidence for communication of the species across the North Atlantic during the early or middle Tertiary.