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A cylindrical permineralized conifer seed cone has been identified from the Officer Member of the Trowbridge Formation, near Izee, in east-central Oregon. The cone is preserved in a Middle Jurassic (Callovian) marine calcium carbonate concretion, associated with araucarian seed cones, conifer twigs and wood, cycad seeds, fern rachides, and lycopodialean remains and was prepared by the cellulose acetate peel technique. The specimen is abraded, 2.8 cm long and 1.3 cm wide, and consists of a cone axis with helically arranged bract/scale complexes, with a large ovuliferous scale and a broad, flattened bract. The bract/scale trace arises as a cylindrical unit from the cone axis, in which the bract and scale traces are separated by ground tissue. The traces separate immediately in the cortex to form a crescent-shaped bract trace and a horseshoe-shaped scale trace with associated sclerenchyma bands that form two triangular bundles toward the distal end of the scale. Ovuliferous scale tissue covers one inverted seed per scale, forming a pocket that contains the seed. Seeds are attached at the chalaza to the inside of the pocket. Seed integuments have an outer epidermis of isodiametric cells with dark contents; one or two layers of palisade cells, occasionally appearing in I-beam configuration; and several inner layers of randomly arranged cells. The nucellus is adnate to the integument, to near the apex, where it forms a cellular mound of tissue. Cylindrical cones with helically arranged bract/scale complexes, bract and scale free to the base, one seed per scale enclosed in a pocket, and triangular sclerenchyma bands are characteristic of the genus Vararaucaria, which recently has been placed in the extinct conifer family Cheirolepidiaceae. This third species extends the known range of Pararaucaria from the Southern Hemisphere to the Northern Hemisphere and emphasizes that the association of araucarian and pararaucarian conifers extended over a wide geographic area during the Jurassic. [ABSTRACT FROM AUTHOR]

This study describes a specimen that extends the oldest fossil evidence of Pinus L. to the Early Cretaceous Wealden Formation of Yorkshire, UK (131-129 million years ago), and prompts a critical reevaluation of criteria that are employed to identify crown group genera of Pinaceae from anatomically preserved seed cones. The specimen, described as Pinus yorkshirensis sp. nov., is conical, 5 cm long, and 3.1 cm in maximum diameter. Bract/scale complexes are helically arranged and spreading. Vasculature of the axis forms a complete cylinder with few resin canals in the wood, and the inner cortex is dominated by large resin canals. Bracts are short, with two resin canals, and separate from the scale base laterally. Distally, the ovuliferous scales broaden and thicken to form a rhomboidal apophysis with a dorsal umbo, characters found only in the genus Pinus among living conifers. Resin canals enter the ovuliferous scale abaxial to the vascular tissue, which divides distally to form a row of adaxially convex bundles. A short interseminal ridge separates two inverted and winged seeds on the adaxial surface of the ovuliferous scale. Seeds contain megagametophyte tissue and polycotyledonary embryos. Numerical cladistic analysis of anatomically preserved seed cones yields a wellresolved phylogeny of crown and stem group Pinaceae that is roughly concordant with the results of analyses that include living species only. All of the included species of Pinus form a clade with three very Pinus-like species that currently are assigned to the stem genus Pityostrobus. These results call to question the utility of traditional methods for assigning fossil seed cones to Pinus, resolve relationships among stem and crown group genera, and highlight the unnatural circumscription of Pityostrobus. This suggests that some species of Pityostrobus may actually represent the genus Pinus, and it demonstrates that the evolutionary diversification of Pinaceae began earlier than previously recognized from fossil evidence. [ABSTRACT FROM AUTHOR]