3,103 research outputs found
R.A. Taylor photograph, Rothwell Fair, 1989.
No full textPhotograph of William Thurston's Seddon Atkinson - YHV441T - Orbiter load, taken Rothwell, May 1989
R.A. Taylor photograph, Rothwell Fair, 1991.
No full textPhotograph of William Thurston Junior's ERF with Zipper load, taken Market Hill, Rothwell, May 1991
Fossil Ophioglossales in the Paleocene of Western North America.
No full textVegetative and fertile frond segments of Botrychium have been recovered from Paleocene deposits of central Alberta, Canada. Specimens are preserved as coalified compressions that yield information about frond structure, sporangia, and spore ultrastructure. These fossils, described as Botrychium wightonii sp. nov., establish a megafossil record for the Ophioglossales, and demonstrate that modem-appearing species of the order were present in western North America by the earliest Tertiary. The largest vegetative fragments are up to 4.6 cm long and tripinnately compound, with opposite to subopposite branching. Ultimate segments are pinnatifid with dentate pinnules and open dichotomous venation. Fertile specimens are also tripinnately compound with a long rachis and subopposite to alternate pinnae. Sporangia are either submarginal and superficial, or marginal, and are all directed toward one surface of the pinnule. They are ovoid to subspheroidal and 0.8-2.0 mm in diameter. Some sporangia are apparently stalked, while others appear to be sessile. This variation results both from the ultimate frond segments being compressed in several different planes, and the fossils being exposed at different levels. Spores macerated from the sporangia are radial and trilete, and range 30-67 ,um in diameter. Most are psilate, but some have a densely striate surface
Trawetsia princetonensis gen. et sp. nov. (Blechnaceae): a permineralized fern from the Middle Eocene Princeton Chert
No full textTrawetsia princetonensis Smith, Stockey, Nishida & Rothwell gen. et sp. nov. is described from several permineralized rhizomes, stipes, and higher-order frond members of a blechnoid fern that have been identified from the Middle Eocene Princeton Chert of British Columbia. Rhizomes bear stipes arising from all sides of the stem as well as diarch adventitious roots. The dictyostelic rhizomes are up to 16 mm across and have five to seven amphiphloic cauline bundles that are capped internally and externally by sclerenchyma. Ground tissue, where well preserved, is transitional from arenchymatous to parenchymatous, with abundant small sclerotic nests found throughout the pith and cortex. Multicellular scales are borne on the rhizome but are sparse and do not imbricate. At least three orders of frond material are preserved: stipes, primary pinnae, and laminar pinnules. Stipes have an adaxial groove, two adaxial hippocampiform bundles, and seven or fewer small, circular bundles arranged in an abaxial U-shaped arc. In distal sections of the rachis, the vascular bundles are reduced to three or fewer. Ground tissue of the stipe has sclerenchyma nests near the base but distally becomes completely aerenchymatous, further evidence that the Princeton Chert preserves an ancient wetland environment. This fossil material expands our knowledge of fern diversity from the Princeton Chert locality, which also includes osmundaceous, dennstaedtioid, and dryopterid ferns, and it contributes to the understanding of the timing and evolution of derived Filicales. While the vegetative anatomy of this fern allies it with the Blechnaceae, the lack of attached fertile fronds precludes the possible recognition of T. princetonensis as a fossil representative of a modern genus or perhaps even a living species
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No full textHere is a curious book. Its title-page declares "The Artist's Book of Fables" but its pre-title-page has "Fables, Original and Selected, with a Memoir of the Author." After that title-page, it is identical with "Fables, Original and Selected" as in our copy printed by John Murray in 1833. There is again an AI at the front and an index of engravings and engravers at the back. I found that copy twenty years ago. I had found an inferior copy twenty-two years before that. At that time, I noted Aesopic fables here including "Stone Broth" and "The Mouse and the Oyster."This is a hardbound book (hard cover)James Northcote, R.A
The Role of Hydropteris pinnata gen. et. sp. nov. In Reconstructing the cladistics of Heterosporous Ferns.
No full textLarge segments of intact plants that represent a heterosporous fern have been discovered within an aquatic plant community from the Late Cretaceous St. Mary River Formation near Cardston in southern Alberta, Canada. Branching rhizomes of Hydropteris pinnata gen. et sp. nov. are 1-2 mm wide. They produce fronds at intervals of 2-12 mm and bear numerous elongated roots. Fronds, up to approximately 6 cm long, are pinnate with subopposite to alternate pinnae that exhibit anastomosing venation. Large, multisoral sporocarps occur at the junctures of the rhizome and frond rachides. Both microsporangiate massulae and megaspore complexes occur within each sporocarp. Megaspore complexes are assignable to the sporae dispersae genus Parazolla Hall. Microspores are trilete, smooth-walled, and are embedded in episporal material of the massulae. A numerical cladistic analysis indicates that the heterosporous aquatic ferns are monophyletic, and not as closely related to either schizaeaceous or hymenophyllaceous ferns as they are to some other filicaleans. Systematic revisions are proposed to reflect newly recognized cladistic relationships within the heterosporous clade, and character originations in the evolution of heterosporous aquatic ferns are evaluated. Hydropteridaceae fam. nov. is proposed, and included with Salviniaceae and Azollaceae in the Hydropteridineae subord. nov., and the Hydropteridales Willdenow
Anatomically Preserved Williamsonia (Williamsoniaceae): Evidence for Bennettitalean Reproduction in the Late Cretaceous of Western North America
No full textAn anatomically preserved ovulate cycadeoid cone has been discovered in Upper Cretaceous (Campanian) sediments of Vancouver Island, British Columbia, Canada. The specimen is preserved by calcareous cellular permineralization and displays diagnostic features of the genus Williamsonia Carruthers. The cone consists of a receptacle from which tightly packed interseminal scales and ovulate sporophylls with terminal ovules diverge over an arc of ca. 300°. Adjacent interseminal scales interdigitate and form a continuous tissue. Seeds are erect and more or less round in cross sections at all levels, and a cupule is not produced. The sarcotesta consists of multicellular peglike projections. The nucellus is attached to the integument only at the chalaza and is vascularized by a shallow cup of tracheids. Apically, the nucellus narrows to a solid finger-like projection that fits tightly into the base of the micropylar canal. A pollen chamber is not produced. Nucellar cells are often separated from each other and are associated with large, hollow structures that represent pollen tubes similar to those in living conifers. Cellular megagametophytes and immature embryos are also preserved in some seeds. Williamsonia bockii sp. nov. represents the most recent seed cone of the Williamsoniaceae and is the first anatomically preserved reproductive structure of this family to be discovered in western North America. It reveals new features for the family Williamsoniaceae and allows for the interpretation of several additional facets of reproductive biology in the Bennettitales, particularly pollen tube production, pollination biology, and mode of fertilization
The Aquatic Angiosperm Trapago angulata from the Upper Cretaceous (Maastrichtian) St. Mary River Formation of Southern Alberta.
No full textA floating aquatic dicot with leaves assignable to Trapago angulata has been characterized from Upper Cretaceous (Maastrichtian) deposits of the St. Mary River Formation in southern Alberta, Canada. Reconstruction of the plant is based on nearly 500 specimens of various isolated and attached organs. Prominent floating rosettes of leaves were interconnected by submerged horizontal rhizomes with a distinct, crenulate surface and formed dense mats at the surfaces of small freshwater ponds. At least eight different leaf morphologies were produced. Rosettes bore opposite pairs of simple leaves and compound leaves with three, five, seven, nine, and possibly 11 leaflets. Highly dissected, submerged leaves of differing morphologies occur on rosette-bearing axes and rhizomes. Paired bud scales at the nodes of the crenulate rhizomes subtend both rhizome leaves and elongate, branched roots. Solitary flowers on long pedicels are attached in the axils of compound leaves. These remains are compared to those described as Quereuxia angulata (Newberry) Kryshtofovich from Russia, and extant Trapa L. Specimens from Russia, while showing leaves of mor- phology similar to that of T. angulata, differ in growth and branching pattern, supporting the interpretation that they are indeed different genera. Although Trapago has commonly been placed in the Trapaceae, the similarities between extant Trapa and Trapago could be attributed to convergence, and the familial affinities of the fossil remain uncertain
Cobbania corrugata (Lesquereux) comb. nov. (Araceae): A floating aquatic aroid from the Upper Cretaceous of western North America
No full textThe fossil record of aquatic flowering plants broadens our understanding of their former diversity and origins from terrestrial ancestors. This paper describes a floating aquatic monocot from 71 whole plants and several isolated leaf fragments from Upper Cretaceous oxbow lake sediments in the Dinosaur Park Formation, Alberta, Canada. The new material is represented by rosettes of leaves and roots attached to short stems that are interconnected by stolons and corresponds to the fossil aroid originally described as Pistia corrugata Lesquereux. Up to six plants have been found interconnected on a single slab suggesting that these plants grew in extensive floating mats covering lakes and calm stretches of rivers. Stems have up to six leaves and large numbers of branched aquatic roots. The leaf is trumpet-shaped with an elongate clasping petiole, large aerenchymatous base, and a nearly circular blade rim. Leaf bases are often filled with sediment giving the leaf the appearance of having a basal pouch. Petioles have 6–9 veins that divide into an upper and lower set, and veins converge at an apical notch. A submarginal collective vein and at least two marginal veins with branching veins form the leaf rim. A series of dichotomizing and anastomosing veins characterize the adaxial leaf surface. Tertiary and quaternary veins form polygonal areolae. Leaf surfaces are covered in trichomes that, like those in Pistia stratiotes, probably aided in buoyancy. A reconstruction of the plant is presented. Based on unique leaf morphology, these fossil plants are clearly not assignable to the genus Pistia and are described as Cobbania corrugata (Lesquereux) Stockey, Rothwell et Johnson gen. et comb. nov. Recent systematic analyses using molecular characters resolve two separate origins of floating aquatic aroids included in the duckweeds and the genus Pistia. This new fossil genus increases our understanding of colonization of aquatic habitats by revealing a third possible origin of the floating aquatic habit within Araceae
Speirseopteris orbiculata gen. et sp. nov. (Thelypteridaceae), a derived fossil filicalean from the Paleocene of western North America.
No full textAn apparently exindusiate filicalean fern with radial sori, sporangia with a vertical annulus, and monolete spores occurs in Paleocene sediments ca. 57 million years old of central Alberta, Canada. Specimens are preserved as coalified compressions and show features of frond morphology and venation, sporangium morphology and dehiscence mechanism, number of spores per sporangium, and spore fine structure. Fronds have a deltoid blade region and are pinnate þ pinnatifid, with fertile pinnules ranging to slightly smaller than vegetative pinnules and with simpler venation. Venation is open, with each lobe of the pinnatifid pinnule having a midvein from which laterals diverge in an alternate pattern. Laterals of vegetative pinnule lobes fork once and terminate at the margin, whereas those of fertile pinnule lobes are unbranched. Sori are round with numerous sporangia and are positioned under a vein. Each sporangium has a vertical annulus that is not interrupted by the stalk and produces ca. 64 spores. Spores are bean shaped and monolete, measuring 26– 36 mm long, with exospore that is dense and sculptured by minute scabrae. Perispore is not preserved. This fern, named Speirseopteris orbiculata gen. et sp. nov., displays characters that are diagnostic of the highly derived filicalean families and is assigned to the Thelypteridaceae. To a lesser extent, it also resembles the Dryopteridaceae, emphasizing that modern fern genera existed among many extinct genera during the late Cretaceous and Paleogene
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