Lower Cretaceous conifers from Apple Bay, Vancouver Island: Picea-like leaves, Midoriphyllum piceoides gen. et sp. nov. (Pinaceae)This paper is one of a selction of papers published on the Special Issue on Systematics Research.

Botany ◽  
2008 ◽  
Vol 86 (7) ◽  
pp. 649-657 ◽  
Author(s):  
Ruth A. Stockey ◽  
Nicholas J.P. Wiebe
Keyword(s):  
Cross Section ◽  
Lower Cretaceous ◽  
Leaf Shape ◽  
Guard Cells ◽  
Vancouver Island ◽  
Vascular Bundles ◽  
Special Issue ◽  
Fossil Leaves ◽  
Transfusion Tissue ◽  
Resin Canals

A diverse assemblage of fossil conifer leaves was identified in calcareous marine concretions from the Lower Cretaceous (Valanginian–Hauterivian) Apple Bay locality, Vancouver Island. Of the hundreds of isolated leaf fragments, most show affinities to Pinaceae. Leaves with closest similarities to Picea (spruce) were studied using cellulose acetate peels. Picea-like leaves vary in cross-section from rhomboidal, pentagonal, triangular, to ovoid. One fused vascular bundle with a centrally located ray and abaxial sclerenchyma is surrounded by a circular endodermis and transfusion tissue. Mesophyll is plicate containing two lateral external resin canals surrounded by a sclerenchyma sheath. Hypodermal fibres are one to three layers thick, except in areas of stomata. Leaves are amphistomatic, with sunken guard cells. Vascular bundles are identical anatomically to Picea; however, plicate mesophyll is similar to that in leaves of Pinus. Extensive sclerenchyma in the hypodermis and surrounding resin canals differs from that in most extant Picea. The major difference between these leaves and those of Picea is leaf shape. These fossil leaves probably belong to an extinct pinaceous conifer, and are described as Midoriphyllum piceoides gen. et sp. nov. Similar evidence from Cretaceous seed cones suggests that like the angiosperms, the Pinaceae were undergoing rapid mosaic evolution during the Lower Cretaceous.

Anemia quatsinoensis sp. nov. (Schizaeaceae), a Permineralized Fern from the Lower Cretaceous of Vancouver Island

2006 ◽  
Vol 167 (3) ◽  
pp. 665-674 ◽  
Author(s):  
Genaro R. Hernandez‐Castillo ◽  
Ruth A. Stockey ◽  
Gar W. Rothwell
Keyword(s):  
Lower Cretaceous ◽  
Vancouver Island

Solenostelopteris skogiae sp. nov. from the Lower Cretaceous of Vancouver Island

2006 ◽  
Vol 119 (5) ◽  
pp. 525-532 ◽  
Author(s):  
Stefan A. Little ◽  
Ruth A. Stockey ◽  
Gar W. Rothwell
Keyword(s):  
Lower Cretaceous ◽  
Vancouver Island

Fossil flowers and leaves of the Ebenaceae from the Eocene of southern Australia

1985 ◽  
Vol 63 (10) ◽  
pp. 1825-1843 ◽  
Author(s):  
James F. Basinger ◽  
David C. Christophel
Keyword(s):  
Guard Cells ◽  
Epidermal Cells ◽  
Fossil Leaves ◽  
Extant Species ◽  
Late Tertiary ◽  
The Family ◽  
Fossil Flowers ◽  
Subsidiary Cells ◽  
Clay Lenses ◽  
Coal Measures

Numerous flowers and a diverse assemblage of leaves are mummified in clay lenses in the base of the Demons Bluff Formation overlying the Eastern View Coal Measures. Fossil localities occur in the Alcoa of Australia open cut near Anglesea, Victoria, Australia. Flowers are tubular, less than 10 mm long, and about 5 mm wide. Four sepals are connate forming a cup-shaped calyx. Four petals are fused in their basal third and alternate with sepals. Flowers are all unisexual and staminate. Stamens are epipetalous and consistently 16 in number, arranged in 8 radial pairs. Pollen is subprolate, tricolporate, and about 32 μm in diameter. The exine is smooth to slightly scabrate. A rudimentary ovary occurs in some flowers. Sepals usually have a somewhat textureless abaxial cuticle with actinocytic stomata. Some sepals, however, have frill-like cuticular thickenings over some abaxial epidermal cells and some subsidiary cells with pronounced papillae overarching guard cells. One of the more common leaf types found associated with the flowers is characterized by the same peculiar cuticular thickenings and overarching papillae on subsidiary cells that occur on sepals. This cuticular similarity indicates that flowers and leaves represent a single taxon. Leaves are highly variable in size and shape but are consistently entire margined, with pinnate, brochidodromous venation. The suite of features characterizing the flowers is unique to the Ebenaceae. Flowers of many extant species of Diospyros (Ebenaceae) closely resemble the fossil flowers. Fossil leaves, too, are typical of leaves of extant Diospyros. Both flowers and leaves are considered conspecific and have been assigned the name Austrodiospyros cryptostoma gen. et sp. nov. The Anglesea fossils represent one of the earliest well-documented occurrences of the Ebenaceae and are the earliest known remains of Ebenaceae from Australia. They support the hypothesis of a Gondwanan origin for the family with late Tertiary diversification in the Malesian region.

Cultural Forests in Cross Section: Clear-Cuts Reveal 1,100 Years of Bark Harvesting on Vancouver Island, British Columbia

2019 ◽  
Vol 84 (3) ◽  
pp. 516-530 ◽  
Author(s):  
Jacob K. Earnshaw
Keyword(s):  
British Columbia ◽  
Cross Section ◽  
Growth Ring ◽  
Vancouver Island ◽  
Forest Harvesting ◽  
Contact Period ◽  
Old Growth ◽  
Ancient Forest ◽  
Post Impact ◽  
Bark Peeling

Culturally modified trees (CMTs) provide tangible evidence of long-term forest use by Indigenous peoples. In Northwest Coast cedar forests, this record rarely spans beyond the last three centuries because older bark-harvest scars have been obscured through taphonomic processes such as natural healing and decay. Thus, archaeological visibility and identification are hindered. Here, I recover chronologies of ancient forest harvesting using a post-impact assessment methodology of targeting old-growth clear-cuts in southern Nuu-chah-nulth territories on the west coast of Vancouver Island, British Columbia, Canada. Bark-peeling scars are identified and dated in cross section by growth-ring patterns of recently logged trees. Approximately half of all bark-peeling scars are “embedded” inside healing lobes, suggesting at least half of all such CMTs are effectively invisible in standing forests. Features in these post-impact surveys predated those discovered in conventional archaeological impact assessments by a mean of almost a century. Additionally, one of the oldest continually used cultural forests ever recorded, dating to AD 908, is found in the Toquaht Nation traditional territory. These findings uncover measurable frequencies of cedar-bark harvesting generations prior to the contact period and reveal the inadequacy of heritage protections for old-growth cedar stands.

scholarly journals Fossil Angiosperm Leaves: Paleobotany's Difficult Children Prove Themselves

2008 ◽  
Vol 14 ◽  
pp. 319-333 ◽  
Author(s):  
Peter Wilf
Keyword(s):  
Leaf Shape ◽  
Leaf Traits ◽  
Plant Ecology ◽  
Feeding Damage ◽  
Leaf Architecture ◽  
Research Areas ◽  
Fossil Leaves ◽  
Past Climate Change ◽  
Scientific Value ◽  
Time Extinction

The great bulk of the angiosperm fossil record consists of isolated fossil leaves that preserve abundant shape and venation (leaf architectural) information but are difficult to identify because they are not attached to other plant organs. Thus, poor taxonomic knowledge has tempered the tremendous potential of fossil leaves for constructing finely resolved records of biodiversity through time, extinction and recovery, past climate change and biotic response, paleoecology, and plant-animal associations. Moreover, paleoecological and paleoclimatic interpretations of fossil leaves are in great need of new approaches. Recent work is rapidly increasing the scientific value of fossil angiosperm leaves through advances in traditional paleobotanical reconstruction, phylogenetic understanding of both leaf architecture and the response of leaf shape to climate, quantitative plant ecology using measurable, correlatable leaf traits, and improved understanding of insect leaf-feeding damage. These emerging areas offer many novel opportunities to link paleoecology and neoecology. Increased collaboration across traditionally separate research areas is critical to continued success.

Structural bionic design for thin-walled cylindrical shell against buckling under axial compression

2011 ◽  
Vol 225 (11) ◽  
pp. 2619-2627 ◽  
Author(s):  
D Xing ◽  
W Chen ◽  
J Ma ◽  
L Zhao
Keyword(s):  
Cylindrical Shell ◽  
Axial Compression ◽  
Cross Section ◽  
Cylindrical Shells ◽  
High Load ◽  
Vascular Bundles ◽  
Bionic Design ◽  
Load Bearing ◽  
Thin Walled ◽  
The Cross

In nature, bamboo develops an excellent structure to bear nature forces, and it is very helpful for designing thin-walled cylindrical shells with high load-bearing efficiency. In this article, the cross-section of bamboo is investigated, and the feature of the gradual distribution of vascular bundles in bamboo cross-section is outlined. Based on that, a structural bionic design for thin-walled cylindrical shells is presented, of which the manufacturability is also taken into consideration. The comparison between the bionic thin-walled cylindrical shell and a simple hollow one with the same weight showed that the load-bearing efficiency was improved by 44.7 per cent.

A Perithecial Sordariomycete (Ascomycota, Diaporthales) from the Lower Cretaceous of Vancouver Island, British Columbia, Canada

2013 ◽  
Vol 174 (3) ◽  
pp. 278-292 ◽  
Author(s):  
Allison W. Bronson ◽  
Ashley A. Klymiuk ◽  
Ruth A. Stockey ◽  
Alexandru M. F. Tomescu
Keyword(s):  
British Columbia ◽  
Lower Cretaceous ◽  
Vancouver Island

scholarly journals Introduction to the special issue on rehabilitation robotics

Robotica ◽  
1998 ◽  
Vol 16 (5) ◽  
pp. 485-485 ◽  
Author(s):  
M. Hillman
Keyword(s):  
Research And Development ◽  
Cross Section ◽  
Elderly Population ◽  
Medical Engineering ◽  
Rehabilitation Robotics ◽  
Development Projects ◽  
Special Issue ◽  
Robotic Technology ◽  
Wide Range ◽  
The University

This special issue of “Robotica” gives an opportunity to present a cross-section of the wide range of research and development projects in rehabilitation robotics. Rehabilitation Robotics (RR) is the application of robotic technology to the rehabilitative needs of people with disabilities as well as the growing elderly population. The papers were originally presented at the ICORR'97 conference, organised by the Bath Institute of Medical Engineering and held in April 97 at the University of Bath. ICORR'97 was the fifth in the series of International Conferences on Rehabilitation Robotics and, after a break of three years, was a welcome and overdue time for sharing of ideas between workers in the field.

scholarly journals Morphological and Anatomical Studies of Hippocrepis L. Genus in Turkey

2019 ◽  
Vol 37 ◽  
Author(s):  
K. YETISEN ◽  
C. ÖZDEMIR
Keyword(s):  
Cross Section ◽  
Vascular Bundle ◽  
The Other ◽  
Vascular Bundles ◽  
Stem Anatomy ◽  
Anatomical Studies ◽  
Anatomical Features

ABSTRACT: In this study, the morphological and anatomical features were investigated of three taxon of Hippocrepis L. species which spreading naturally in Turkey. In the morphological part of the study, H. unisiliquosa subsp. unisiliquosa’s stem is erect or decumbent. The species H. ciliata’s Willd. stem is erect. H. multisiliquosa’s L. stem is decumbent. The fruit of H. multisiliquosa is much more convoluted than the other two taxa. There are cilia on the fruit of H. ciliata, but there are not found any cilia the other two taxa. The stem anatomy of all the studied taxa is hexagonal. In the stem cross section of H. ciliata 12-14 vascular bundle are found, H. unisiliquosa subsp. unisiliquosa 12-15 and H. multisiliquosa 12-13. Leaf vascular bundles are arranged regularly, H. unisiliquosa subsp. unisiliquosa have 18-20, H. ciliata have 6-8, H. multisiliquosa have 9-13 vascular bundles.

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