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Premise of research. The southern conifer family Podocarpaceae inhabits wet environments and is highly diverse in its vegetative and megasporangiate structures. The Podocarpaceae are today divided into a tropical clade and a prumnopityoid clade. We study the morphology and anatomy of leaves and megasporangiate cones at postpollination and the maturity of two native Patagonian Podocarpaceae, Saxegothaea conspicua (tropical clade) and Lepidothamnus fonkii (prumnopityoid clade). We aim to add to the knowledge of the South American Podocarpaceae and to interpret their unique morphologies to aid in our understanding of the deep and cryptic fossil record of the family and its relationships with other conifer families. Methodology. Specimens of S. conspicua and L. fonkii were collected in natural and cultivated populations of southern Chile and imaged using different macro- and microscopic techniques, including epifluorescence, bright-field, and scanning electron microscopy. Pivotal results. Leaf and megasporangiate cone anatomy and morphology are described in detail for both species. For S. conspicua , we observed a helical to slightly planate leaf arrangement with leaf reorientation, expanded leaves without accessory transfusion tissue, an apparent lack of vascularization of the epimatium (which is bikeeled and does not surround the ovule completely), and nonsaccate pollen germinating on the bract toward the protruding nucellus. For L. fonkii , we observed the absence of leaf hypodermis and resin canals, the presence of a micropylar hook in the ovule and seed integument, bisaccate pollen germinating within the ovule, cone bracts reduced in number and size, and a basal receptacle-like structure. Conclusions. Leaf arrangement in Saxegothaea shows an intermediate condition between the primary helical phyllotaxis common in the family and the secondary planate arrangement seen in most podocarps with expanded leaves. Lepidothamnus fonkii was determined to have a false receptacle (i.e., a receptacle-like structure originated from vegetative basal bracts rather than by sterile ovuliferous complexes). The presence of a false receptacle in L. fonkii is a morphological novelty in Podocarpaceae. [ABSTRACT FROM AUTHOR]

Premise of research. A new Early Jurassic species of Cupressaceae is reconstructed from the Cañadón Asfalto Formation in Argentina, based on impressions of foliage and attached and dispersed seed and pollen cones. Methodology. Over 230 specimens were examined using reflected-light microscopy and epifluorescence. Relevant extant taxa were studied for structural comparisons using herbarium specimens and living material from botanical gardens. Relationships of the new conifer were assessed in the context of currently known fossil and living taxa and used to evaluate morphological trends in the early evolution of Cupressaceae. Pivotal results. The new species, Austrohamia asfaltensis D.L. Contreras, I.H. Escapa, R.C. Iribarren, & N.R. Cúneo, has helically arranged, dorsiventrally flattened leaves that are rotated into semiplanar orientation, seed cones consisting of helically arranged coriaceous ovuliferous complexes that each bear two seeds and have a distinct abaxial keel and acuminate apex, and pollen cones that occur in clusters subtended by keeled bracts. Specimens show evidence that normal vegetative shoot growth continues from the pollen cone clusters, a condition that appears to characterize living Cunninghamia and some extinct conifers but not Taiwania. The new species is assignable to the genus Austrohamia , which shares a combination of characteristics consistent with the Cunninhamioideae and Taiwanioideae subfamilies of the Cupressaceae. It is distinct from other Austrohamia species, most notably by having seed cones that are twice as large and with many more ovuliferous complexes. Conclusions. The new species expands the known morphological diversity of Austrohamia , which is the oldest recorded genus of Cupressaceae based on reproductive material, and provides a new early occurrence of the family in the Southern Hemisphere. The development of a whole-plant concept enabled morphological comparisons over a broad range of traits and with taxa known from different combinations of organs, which has provided additional insights into the early evolution of Cupressaceae. [ABSTRACT FROM AUTHOR]

Premise of research. Numerous leaf remains of pteridosperms occur at a new locality of the Early Jurassic Cañadón Asfalto Formation, in Patagonia, Argentina. Fossils consist of adpressions with superb cuticular preservation and are herein assigned to Lepidopteris (Peltaspermaceae). Methodology. Fossils were studied using normal light, epifluorescence, and scanning electron microscopy. The cuticles of 25 specimens were chemically prepared following standard methods. The remains were described in detail and compared with other pteridosperm genera and Lepidopteris species. Pivotal results. We erect Lepidopteris scassoi sp. nov. Elgorriaga, Escapa et Cúneo, based on its novel combination of characters. Among other features, L. scassoi has a bipinnate-tripinnatifid architecture, smooth rachis, 1–3 pairs of intercalary pinnules, and entire to deeply lobed pinnules with pinnate venation. Fronds are amphistomatic with a 0.5–0.7∶1 adaxial to abaxial ratio; stomata occur scattered on rachides and pinnules and have a ring of usually seven subsidiary cells with papillae oriented toward the stomatal pit; and the guard cells are sunken. A single solid papilla is usually present on epidermal cells of pinnules and pinnae. Structures resembling isolated Peltaspermum disks, with similar stomata as L. scassoi , were found in the same locality. Conclusions. We interpret L. scassoi and other members of its lineage as fast-growing, long-lived shrubby to herbaceous plants that thrived in waterside environments. Lepidopteris scassoi represents the youngest occurrence of the genus by more than 20 Myr. Lepidopteris and Dicroidium lineages, dominant in Southern Hemisphere Triassic ecosystems, show a similar overall pattern of origination (Late Permian), diversification (late Early-Middle Triassic), and decline (Late Triassic), with relict occurrences during the Early Jurassic. The systematic affiliation of a considerable number of Mesozoic pteridosperm records remains contentious, and future efforts should be oriented toward a better understanding of the position of each group on the gymnosperm tree of life. [ABSTRACT FROM AUTHOR]

We present a whole-plant concept for a genus of voltzialean conifers on the basis of compression/impression and permineralized material from the Triassic of Antarctica. The reconstruction of the individual organs is based on a combination of organic connections, structural correspondences, similarities in cuticles and epidermal morphologies, co-occurrence data, and ex situ palynology. The affiliated genera of organs include trunks, branches, and roots (Notophytum); strap-shaped leaves with parallel venation {Heidiphyllum compressions and permineralized Notophytum leaves); seed cones (Telemachus and Parasciadopitys); pollen cones (Switzianthus); and bisaccate pollen of Alisporites type. Structural similarities lead us to suggest that Parasciadopitys is the permineralized state of a Telemachus cone and should be treated as a junior synonym. Biotic interactions involving the reconstructed conifer genus include plant-insect interactions (oviposition by Odonata) and not less than five different types of plant-fungal interactions, including two distinct endomycorrhizal associations, two probable seed parasites, and epiphyllous fungi. A representative whole plant is reconstructed as a 10-15-m-tall, seasonally deciduous forest tree with a vertical, narrow-conical crown shape. We interpret these Telemachus trees as the dominant components of peat-forming conifer swamps, forest bogs, and immature bottomland vegetation in the Triassic high-latitude river basins of southern Gondwana. In architecture, growth habit, and many ecological characteristics, the Telemachus conifers appear to be comparable to extant larch (Larix). Owing to the large amount and often exquisite preservation of the material, this conceptual whole-plant genus represents one of the most completely reconstructed ancient conifer taxa to date. [ABSTRACT FROM AUTHOR]