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Premise of research. Numerous large permineralized fossil seeds from the Jurassic of Haida Gwaii, western Canada, provide evidence for the mode and tempo of cycad evolution. Methodology. Fossil seed specimens are studied from external morphology and serially sectioned by the classic cellulose acetate peel technique to reveal anatomical features of the integument, vascular system, nucellus, and gametophyte. Fossils are compared to living cycad seeds that are also examined from external views, dissections, and anatomical preparations. Pivotal results. The fossil seeds are described as Traskia maahlae gen. et sp. nov. Features of the integument and vascular system reveal that T. maahlae is a stem group cycad that shares seed architecture and mode of germination with living Cycas spp. Conclusions. Traskia maahlae adds to a growing body of paleontological data on stem and crown group cycads. Results suggest that modern pollination and postpollination biology and the two contrasting modes of cycad seed germination evolved during the Mesozoic but that crown group cycad species may not have appeared until the Cenozoic. [ABSTRACT FROM AUTHOR]

Premise of research. A single cylindrical conifer seed cone has been discovered in a calcium carbonate marine concretion from the Upper Cretaceous Eden Main Quarry, dated as early Coniacian (∼89 Ma), 35 km northwest of Courtenay on Vancouver Island, British Columbia, Canada. Methodology. The specimen was sectioned with a rock saw, and serial sections were prepared using the classical cellulose acetate peel technique. Peel sections were mounted on microscope slides. Reconstructions of the cone and seeds were rendered with Avizo. Pivotal results. The cone is somewhat abraded, at least 2.3 cm long and 1 cm wide, with the apex missing and most of the base coalified. The well-preserved midsection shows bract/scale complexes inserted at a steep angle. The bract/scale complex has a central rhomboidal shaft and two lateral winglike extensions. Xylem of the cone axis is robust, with secondary xylem tracheids that have circular-bordered pits. A single circular vascular trace enters the bract/scale complex. Three resin canals enter the base of the scale and divide to form up to eight or nine canals distally. Six overlapping, inverted winged seeds, ∼8 mm long and 1 mm thick, with two large, fleshy wings are borne on the adaxial surface of each scale. The nucellus is free from the endotesta to its base. Megagametophytes and embryos occur in some seeds. Cells of the megagametophyte have granular contents. This cone shows similarities in overall structure and vasculature to those of living Taiwania (Cupressaceae); however, the fossil cone size is generally larger, with six seeds per scale versus two, and seeds are extremely large and fleshy with a unique submicropylar structure. Conclusions. This cone is compared with living and fossil taxa of Cupressaceae and described as Comoxostrobus rossii gen. et sp. nov. (Cupressaceae subfamily Taiwanioideae), revealing that taiwanioid Cupressaceae were much more diverse and widespread during the Cretaceous. [ABSTRACT FROM AUTHOR]

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]