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Anatomically preserved lycophytes of the Lycopodiales and Selaginellales have been discovered among a diverse assemblage of plants and fungi in carbonate marine concretions at the Apple Bay locality along the shore of Holbert Inlet near the northern end of Vancouver Island, British Columbia, Canada. Lycopodialean stems are plectostelic and actinostelic, branch dichotomously, and are similar to both Lycopodicaulis oellgaardii and Lycoxylon spp. The Selaginella specimens represent the first anatomically preserved Selaginellales with excellent internal cellular preservation in the fossil record, and are described as Selaginella quatsinoense Rothwell et Stockey sp. nov. Stems have three and five exarch, monarch stelar segments, each of which is surrounded by an aerenchymatous endodermis with trabeculae. The leaf base is indented on the adaxial surface, suggesting the position of a ligule. These fossils document that species with diagnostic internal anatomy of modern Lycopodiales and Selaginellales evolved no later than the Valanginian of the early Cretaceous. [ABSTRACT FROM AUTHOR]

Premise of research. Ten anatomically preserved conifer seed cone specimens are preserved on the surfaces of, and within, three interlocking rock fragments of terrestrial limestone discovered as float along the Colville River on the North Slope of Alaska, providing additional evidence for the diversification of taiwanioid Cupressaceae during the Upper Cretaceous–Cenozoic interval. Methodology. Specimens on rock surfaces were measured and photographed, and then serial anatomical thin sections were prepared by the cellulose acetate peel technique. Three-dimensional images of selected specimens were also captured using micro–computed tomography (micro-CT). Pivotal results. The structure of these seed cones is similar to that of living Taiwania cryptomerioides in cone shape, the presence of subtending scalelike leaves, helically arranged and imbricating foliate ovuliferous complexes (OCs), the absence of a separate ovuliferous scale tip, variation in numbers of OCs, and by having two adaxially positioned winged seeds per complex. However, abruptly upturned OC, details of OC vasculature, and distinctive histological features reveal that these seed cones represent a new species of the extinct genus Mukawastrobus. Conclusions. When added to the existing record of fossil seed cones, the new species Mukawastrobus arnoldii highlights the recent discovery that among early-diverging lineages of Cupressaceae, there has been considerable Cretaceous, Paleogene, and Neogene evolution that is reflected by variations among subtle characters that are not recognizable in any but the most completely preserved specimens. [ABSTRACT FROM AUTHOR]

Premise: An anatomically preserved fossil fern sporeling has been discovered in a Lower Cretaceous marine concretion from Vancouver Island, British Columbia, Canada, providing an opportunity to characterize rhizome growth from an extinct species. Methods: The specimen was studied from serial transverse sections prepared by the cellulose acetate peel technique. Results: The rhizome ranges from ~0.7 to 1.1 mm in diameter, has a sclerenchymatous pith, a stele that attains a dictyoxylic architecture, and sclerenchymatous outer cortex, features that are characteristic of osmundaceous rhizomes. Cauline xylem forms a medullated protostele or solenostele at some levels, but is dissected into discrete xylem bundles at others. Fronds diverge in a helical phyllotaxis, range up to 1.1 mm in greatest dimension, and have a C‐shaped trace and outer cortex of sclerotic cells. Inside the sclerenchyma of the petioles are two lateral sclerotic strands and a sclerotic bundle adaxial to the trace. Together, these characters reveal the occurrence of a new species, Todea minutacaulis and provide evidence for developmental changes that occur in the rhizome as the sporeling increased in size. Conclusions: Small size of the specimen, medullated protostelic‐dictyoxylic solenostelar vascular architecture, and incompletely sclerified cells apically reveal that osmundaceous sporeling development has remained constant since at least the Early Cretaceous. Together with Todea tidwellii and Osmunda vancouverensis that also are present in the Apple Bay flora, this sporeling documents the occurrence of a multispecies assemblage of osmundaceous ferns and demonstrates that the genus Todea was diversifying rapidly by the Early Cretaceous. [ABSTRACT FROM AUTHOR]

Premise of research. Two permineralized inflorescences have been found in calcium carbonate concretions from the Eocene Appian Way locality on Vancouver Island, British Columbia, increasing sampling density and helping clarify the pattern of phylogeny for Alismatalean monocots. Methodology. Serial sections of specimens were prepared by the cellulose acetate peel technique and studied with light microscopy. Phylogenetic analyses using a morphological matrix of living and fossil Araceae and Acoraceae were performed using TNT version 1.5 to help establish relationships of the fossil inflorescences. Pivotal results. Inflorescences are cylindrical spikes, >37 mm long and 8.1 mm wide, with a peduncle at least 14.5 mm long, bearing numerous helically arranged, bisexual sessile flowers with hooded tepals. Fruits are trilocular, with basal axile placentation and one seed per locule. Remnants of probable stamens are present in most flowers. Conclusions. Flower structure was compared to those of other petalloid, spicate, bisexual flowers in the monocot families Acoraceae and Araceae (Alismatales). The number of carpels is similar to that in Acorus (Acoraceae) and Spathiphyllum (Araceae, Monsteroideae) and some Pothoideae. Single-seeded ovaries are common in Araceae, while the locules in Acorus contain several apically attached seeds. Phylogenetic analyses place Appianospadix in Proto-Araceae near the base of the aroid tree. This inflorescence with a unique combination of characters is described as Appianospadix bogneri , a new genus and species of Alismatales (family: Araceae). [ABSTRACT FROM AUTHOR]

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: Anatomically preserved evidence for a novel clade of gymnosperms emphasizes diversity of seed plants immediately prior to the appearance of angiosperm fossils in the paleontological record. Methods: Cupulate seeds from the Early Cretaceous Apple Bay locality (Vancouver Island) are described from serial cellulose acetate peels and three‐dimensional reconstruction. Phylogenetic context is assessed through the comparative analysis of gymnosperm seed producing fructifications and maximum parsimony analysis of a revised morphological data set for seed plant phylogeny. Results: Xadzigacalix quatsinoensis gen. et sp. nov. is characterized by an orthotropous ovule with an elongated micropyle and complex integument, enclosed within a radial cupule. The micropylar canal is elongated; and the nucellus extends into the micropyle to seal the post pollination ovule. Except at the apex of the micropyle, the seed is completely enclosed by a parenchymatous cupule with ca. 20 axially elongated secretory ducts. The cupulate seed is produced upon a triangular woody stele, consisting of a parenchymatous pith surrounded by radially aligned tracheids. The stele produces three short terete traces that terminate within the base of the cupule as transfusion tissue at the seed chalaza. Conclusions: Organography, vascularization, nature of the integument and nucellus, and configuration of the micropylar canal distinguish Xadzigacalix quatsinoensis from all other gymnosperm clades. Cladistic analyses suggest the new plant may have affinities with gnetophytes or angiosperms. These results are complemented with a critical re‐evaluation of ovulate structures for Mesozoic gymnosperms, providing new insight into plant diversity immediately antecedent to the explosive diversification of flowering plants. [ABSTRACT FROM AUTHOR]

Anatomically preserved fossil gleicheniaceous fern remains in carbonate marine concretions from Vancouver Island, British Columbia, Canada support the development of a whole plant concept for an Eocene species of Gleichenia , and provide data to develop the first organismal concept for an extinct species of Gleichenia from the Cenozoic fossil record. New information for completing the plant reconstruction includes anatomically preserved pinnule fragments with attached radial exindusinate sori of six to seven annulate sporangia containing trilete spores. While the overall pattern of evolution within Gleicheniaceae remains incompletely understood because well-documented fossils from pre-Cretaceous deposits are inconsistently preserved, this organismal plant concept strengthens evidence that all diagnostic features of the family Gleicheniaceae were present, and that essentially modern species were well-established and diversifying during the Cretaceous and Paleogene. • First whole plant reconstruction of a Cenozoic species of Gleichenia. • Characterized by both external morphology and internal anatomy. • Evidence of stems, frond fragments, and sori of sporangia containing spores. • Essentially modern species of Gleicheniaceae evolved no later than the Paleogene. • Family Gleicheniaceae is inconclusively present in pre-Cretaceous deposits. [ABSTRACT FROM AUTHOR]

An organismal concept for the Late Devonian/Mississippian hydrasperman seed fern Tetrastichia bupatides is developed from specimens collected at Oxroad Bay, East Lothian Scotland and Ballyheigue, County Kerry, Ireland. Specimens include interconnected fragments of stems, frond rachides, pinnae, pinnules, roots, pollen organs with enclosed pre-pollen, and cupules, as well as dispersed ovules. Both morphological and anatomical features are documented. The plant produces an unbranched, upright stem with a branched taproot, and small adventitious roots at the base of the stem. Stems have a mesarch actinostele with sympodial protoxylem architecture. Phyllotaxis ranges from helical to opposite/decussate, with planar fronds that typically fork twice at the base, and then produce pinnules of the Rhodea -type. Compact aggregate pollen organs are attached distally on secondary rachides and are constructed of cruciately forking axes that terminate in inverted, round, simple synangia of six elongated microsporangia attached to a basal pad of tissue. Ovulate cupules of the Calathospermum fimbriatum type are attached at the base of the frond. Ovules possibly could be Salpingostoma dasu or Eospermum oxroadense. Tetrastichia bupatides is now one of the most completely reconstructed of all Devonian-Mississippian hydrasperman seed ferns, and the most ancient gymnosperm for which the pattern of rooting has been established. The occurrence of a taproot at the base of the stem suggests that the plant may exhibit bipolar growth derived from a cotyledonary embryo. • An organismal concept for the seed fern Tetrastichia bupatides is developed. • Structure of fronds, pollen organs, and the rooting system are described. • Interconnections of organs are documented. • Relationships among the most ancient hydrasperman seed ferns are evaluated. [ABSTRACT FROM AUTHOR]

Premise of research. Sixteen compression/impression specimens of a new floating aquatic angiosperm that enrich our knowledge of Late Cretaceous vegetation have been identified from the early Maastrichtian St. Mary River Formation near Cardston, Alberta, Canada. Methodology. Fossils were studied using dégagement and photographed under reflected light. Leaves were morphotyped using methodology in the Manual of Leaf Architecture and compared to other extant and extinct rosette-forming floating aquatic angiosperms. Pivotal results. Stems of this aquatic dicot show determinate growth of floating shoots with opposite/decussate attachment of heterophyllous leaves. Leaves are simple and sessile at the apicalmost node, simple and petiolate at the second node, and compound with three leaflets at nodes 3–6. Compound leaves are petiolate and ternate (trifoliate). Leaflet shape is unlobed, obovate, and symmetrical; base is acute-obtuse; apex angle is obtuse; base shape is convex; petiolar attachment is marginal; apex shape is rounded; and margin is crenate. Primary veins are flabellate to pinnate with three to five basal veins that dichotomize distally. Secondary veins are craspedodromous with uniform spacing and angles. Teeth are of a single order, three per centimeter near apex, and convex-convex; the sinus is angular, and the apex is foraminate. Conclusions. While the basic growth habit of this plant is similar to that of several extant taxa in the Onagraceae, Lythraceae, Plantaginaceae, and Hydrocharitaceae, leaf venation and the presence of compound leaves differ greatly from the living species. In growth habit and the presence of both simple and compound leaves, the new plant is similar to Quereuxia angulata , also found at this fossil site. These fossils are described as a new genus and species, Tolmania aquatica Edmonds, Stockey & Rothwell, which differs from Quereuxia in pattern of heterophylly, venation, larger plant size, stem morphology, and the presence of hydathodes in the leaves. [ABSTRACT FROM AUTHOR]

Rhizomorphic lycopsids constitute the most derived lycophyte clade and some of the world's best-known plant fossils. Arboreous taxa within the clade evolved independently of other nonlycophyte trees. Their rootstocks (rhizomorphs) have distinctive morphologies and anatomies and unusually canalized ontogenies, leading to debates regarding homology and functional morphology. Traditionally referred to form genus Stigmaria , rhizomorphs of arboreous genera are repeatedly isotomous, producing a helical rhizotaxy of abundant determinate appendages (rootlets). Regarded as leaf homologues, reexamination of fossil and living Isoetes "rootlets" suggests some shared genetic and morphological traits with true roots, while maintaining many leaflike phenotypic traits. This logic cannot automatically be extended to the radially symmetrical, rootlet-producing rhizomorph axes, which are inferred to combine developmental programs that distinguish root from shoot in nonlycophytes. Comparative embryogeny of several fossil genera plus Isoetes suggests shared ontogeny and heterochronically driven divergences. The first-formed microphylls and root support the juvenile plant until the rhizomorph is produced laterally as a sui generis organ that rapidly co-opts the role of the first-formed root, transitioning from radial to bilateral to radial symmetry. We reevaluate the conventional view that the rootlets were abscised, despite their superficial origin. Rootlets are common in areas of comparatively low resistance, which suggests low penetrating power. In addition to dissolved minerals, rootlets may have gathered soil CO2 for use within the rhizomorph and/or shoot system, and exposed upwardly directed roots may have been photosynthetic. In soil, rootlets improved anchorage, whereas in open water, largely hollow mature roots may have enhanced stigmarian system buoyancy and nucleated floating peat mats. Examination of hundreds of in situ stumps has failed to locate an uprooted specimen; hollowed-out dead stumps were conduits for materials into potentially dysoxic levels in the substrate. We cannot identify close modern analogues for the ecological role played by these unique trees. [ABSTRACT FROM AUTHOR]

Premise: Nearly 200 araceous leaves and two spadices have been identified among Paleocene fossils from the Blindman River locality near Blackfalds, Alberta, Canada. Although not found in attachment, these probably represent parts of the same extinct plant species. Methods: Specimens were studied using light microscopy. Phylogenetic analyses using a morphological matrix of living and fossil Araceae were performed using TNT version 1.5 to help establish relationships of the fossil leaves and spadices within Araceae and to each other. Results: Leaves are simple with a broad petiole, entire margin, and elliptic to ovate or oblong blade with an acute to slightly rounded apex. A multi‐veined midrib extends into the basal region of the blade. Parallelodromous primary veins of two orders diverge at acute angles, converging with a submarginal vein or at the apex. Transverse veins are opposite percurrent, producing rectangular to polygonal areoles. Higher‐order veins are mixed opposite/alternate. Spadices are cylindrical, with helically arranged, bisexual, perigoniate flowers, each with six free tepals and a protruding style. Fruits are trilocular, with axile placentation and one seed per locule. Conclusions: Leaves are assignable to the fossil genus Orontiophyllum J. Kvaček & S.Y. Sm. as O. grandifolium comb. nov. Spadices are described as Bognerospadix speirsiae gen. et sp. nov. Leaves and spadices each conform to an early‐diverging lineage of Araceae, increasing the known diversity of Proto‐Araceae (viz., subfamilies Gymnostachydoideae and Orontioideae). Together, they provide strong evidence for extinct Proto‐Araceae with novel combinations of characters shortly after the Cretaceous‐Paleogene floral transition. [ABSTRACT FROM AUTHOR]

Premise of research. Early Cretaceous (Valanginian) rocks exposed at Apple Bay (Vancouver Island, Canada) have yielded numerous anatomically preserved bryophytes that have expanded our knowledge of the pre-Cenozoic fossil record of this group. A new moss type with tricostate leaves from Apple Bay combines characters not encountered in moss species recorded previously, warranting in-depth characterization of a new taxon. Methodology. Carbonate concretions containing permineralized fossil material were sectioned using the cellulose acetate peel technique. The resulting acetate peels providing serial sections through the bryophyte specimens were used to reconstruct the habit of the plant and its leaves in two and three dimensions. Pivotal results. We describe a new species of moss in the family Tricostaceae, Tricosta priapiana sp. nov. The anatomy and morphology of the new species justify expanding and refining the diagnoses of Tricostaceae and Tricosta , especially with respect to perigonial branches and the morphology of branch buds. The presence of pseudoparaphyllia surrounding the branch buds supports the pleurocarpous affinities proposed previously for the Tricostaceae. Conclusions. Tricosta priapiana adds to the diversity of tricostate mosses, an extinct group that was intriguingly diverse in the Mesozoic. Nevertheless, the tricostate state is probably a convergent trait, or a trait that may have evolved independently in acrocarpous and pleurocarpous moss lineages in response to similar selective pressures. Still, it remains unclear what such selective pressures may have been, as the paleoclimates and habitats that hosted the tricostate mosses are not well circumscribed, precluding comparisons among the different species and their closest analogs among living multicostate mosses. [ABSTRACT FROM AUTHOR]

Conifers of the taxodiaceous grade of Cupressaceae were more diverse and widespread during the Mesozoic than they are today. The earliest diverging subfamily, Cunninghamioideae, only includes a single extant genus, but has at least 10 fossil genera. Here, two additional cunninghamioid genera are characterized on the basis of permineralized seed cones from the Upper Cretaceous of Hokkaido, Japan. These conifers display seed cone characters typical of cunninghamioids; however, they have a mosaic of characters that are not seen in any reported conifer of Cupressaceae. They are, therefore, designated as two new extinct species: Ohanastrobus hokkaidoensis gen. et sp. nov. and Nishidastrobus japonicum gen. et sp. nov. These newly reported conifers expand the taxonomic and morphological diversity of cunninghamioids. The stratigraphic and paleobiogeographic records of cunninghamioids and other fossil Cupressaceae with foliate seed cones indicate they peak in diversity during the Cretaceous. The living genera Taiwania and Cunninghamia appear during the Albian and Campanian, respectively, and maintain a nearly continuous fossil record through to today, while nearly all other extinct genera of Cupressaceae with foliate cones disappear by the close of the Campanian. As more ancient cunninghamioids are recovered, our understanding of macroevolutionary patterns of this once diverse lineage will be further elucidated. [ABSTRACT FROM AUTHOR]