Dukinfield Henry Scott
Dr Dukinfield Henry Scott FRS HFRSE LLD was a British botanist. The standard author abbreviation D. H. Scott is used to indicate this person as the author. Scott was born in London on 28 November 1854, the fifth and youngest son of architect Sir George Gilbert Scott and his wife Caroline Oldrid. One consequence was that he was of independent financial means and was not affiliated with an academic institution for much of his life. Scott studied Natural Sciences at Oxford University, graduating with his M. A. and went on as a postgraduate at Wurzburg University in Germany. There, he studied under the famous botanist Julius von Sachs, earned his doctorate. From 1882 to 1885, he was Assistant to the Professor of Botany at University College and from 1885 to 1892, Assistant Professor in Biology at the Royal College of Science, South Kensington. In 1892, Scott left the Royal College of Science when he was appointed Honorary Keeper of the Jodrell Laboratory, Royal Gardens at Kew, a position he held for fourteen years.
He published many papers on botany in scientific journals. He did important work in paleobotany as the younger colleague of William Crawford Williamson, one of the founders of paleobotany, he made use of the assistance of his wife to provide illustrations and indexes for his publications as well as to catalogue his collection of fossil slides. He supported the education of women and was the first lecturer in botany at University College who allowed women to attend his classes, he was President of the Royal Microscopical Society from 1904 to 1906. He was president of the Linnean Society from 1908 to 1912, he was elected a member of the Royal Swedish Academy of Sciences in 1916 and a Fellow of the Royal Society in June 1894. In 1930 he was elected an Honorary Fellow of the Royal Society of Edinburgh, he was awarded the Royal Medal of the Royal Society in 1906, the Linnean Medal of the Linnean Society in 1921, the Darwin Medal of the Royal Society in 1926 and the Wollaston Medal of the Geological Society of London in 1928.
He moved with his family to East Oakley House near Basingstoke, in Hampshire in 1906. He continued to publish from there until his death. In 1887 he married Henderina Victoria Klaassen, they had seven children. One of his most brilliant students was Harold Wager, who became his student in botany in 1886 and went on to become a Fellow of the Royal Society of London in 1904. Scott, Dukinfield Henry An Introduction to Structural Biology.. Scott, Dukinfield Henry. Studies in Fossil Botany. A. and C. Black. Scott, Dukinfield Henry; the Evolution of Plants. H. Holt and Co. Works written by or about Dukinfield Henry Scott at Wikisource
The Ordovician is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.2 million years from the end of the Cambrian Period 485.4 million years ago to the start of the Silurian Period 443.8 Mya. The Ordovician, named after the Celtic tribe of the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same rock beds in northern Wales into the Cambrian and Silurian systems, respectively. Lapworth recognized that the fossil fauna in the disputed strata were different from those of either the Cambrian or the Silurian systems, placed them in a system of their own; the Ordovician received international approval in 1960, when it was adopted as an official period of the Paleozoic Era by the International Geological Congress. Life continued to flourish during the Ordovician as it did in the earlier Cambrian period, although the end of the period was marked by the Ordovician–Silurian extinction events.
Invertebrates, namely molluscs and arthropods, dominated the oceans. The Great Ordovician Biodiversification Event increased the diversity of life. Fish, the world's first true vertebrates, continued to evolve, those with jaws may have first appeared late in the period. Life had yet to diversify on land. About 100 times as many meteorites struck the Earth per year during the Ordovician compared with today; the Ordovician Period began with a major extinction called the Cambrian–Ordovician extinction event, about 485.4 Mya. It lasted for about 42 million years and ended with the Ordovician–Silurian extinction events, about 443.8 Mya which wiped out 60% of marine genera. The dates given are recent radiometric dates and vary from those found in other sources; this second period of the Paleozoic era created abundant fossils that became major petroleum and gas reservoirs. The boundary chosen for the beginning of both the Ordovician Period and the Tremadocian stage is significant, it correlates well with the occurrence of widespread graptolite and trilobite species.
The base of the Tremadocian allows scientists to relate these species not only to each other, but to species that occur with them in other areas. This makes it easier to place many more species in time relative to the beginning of the Ordovician Period. A number of regional terms have been used to subdivide the Ordovician Period. In 2008, the ICS erected a formal international system of subdivisions. There exist Baltoscandic, Siberian, North American, Chinese Mediterranean and North-Gondwanan regional stratigraphic schemes; the Ordovician Period in Britain was traditionally broken into Early and Late epochs. The corresponding rocks of the Ordovician System are referred to as coming from the Lower, Middle, or Upper part of the column; the faunal stages from youngest to oldest are: Late Ordovician Hirnantian/Gamach Rawtheyan/Richmond Cautleyan/Richmond Pusgillian/Maysville/Richmond Middle Ordovician Trenton Onnian/Maysville/Eden Actonian/Eden Marshbrookian/Sherman Longvillian/Sherman Soudleyan/Kirkfield Harnagian/Rockland Costonian/Black River Chazy Llandeilo Whiterock Llanvirn Early Ordovician Cassinian Arenig/Jefferson/Castleman Tremadoc/Deming/Gaconadian The Tremadoc corresponds to the Tremadocian.
The Floian corresponds to the lower Arenig. The Llanvirn occupies the rest of the Darriwilian, terminates with it at the base of the Late Ordovician; the Sandbian represents the first half of the Caradoc. During the Ordovician, the southern continents were collected into Gondwana. Gondwana started the period in equatorial latitudes and, as the period progressed, drifted toward the South Pole. Early in the Ordovician, the continents of Laurentia and Baltica were still independent continents, but Baltica began to move towards Laurentia in the period, causing the Iapetus Ocean between them to shrink; the small continent Avalonia separated from Gondwana and began to move north towards Baltica and Laurentia, opening the Rheic Ocean between Gondwana and Avalonia. The Taconic orogeny, a major mountain-building episode, was well under way in Cambrian times. In the early and middle Ordovician, temperatures were mild, but at the beginning of the Late Ordovician, from 460 to 450 Ma, volcanoes along the margin of the Iapetus Ocean spewed massive amounts of carbon dioxide, a greenhouse gas, into the atmosphere, turning the planet into a hothouse.
Sea levels were high, but as Gondwana moved south, ice accumulated into glaciers and sea levels dropped. At first, low-lying sea beds increased diversity, but glaciation led to mass extinctions as the seas drained and continental shelves became dry land. During the Ordovician, in fact during the Tremadocian, marine transgressions worldwide were the greatest for which evidence is preserved; these volcanic island arcs collided with proto North America to form the Appalachian mountains. By the end of the Late Ordovician the volcanic emissions had stopped. Gondwana had by that time neared the South Pole and was glaciated
In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae and protozoa. Bacterial spores are not part of a sexual cycle but are resistant structures used for survival under unfavourable conditions. Myxozoan spores release amoebulae into their hosts for parasitic infection, but reproduce within the hosts through the pairing of two nuclei within the plasmodium, which develops from the amoebula. Spores are haploid and unicellular and are produced by meiosis in the sporangium of a diploid sporophyte. Under favourable conditions the spore can develop into a new organism using mitotic division, producing a multicellular gametophyte, which goes on to produce gametes. Two gametes fuse to form a zygote; this cycle is known as alternation of generations. The spores of seed plants, are produced internally and the megaspores, formed within the ovules and the microspores are involved in the formation of more complex structures that form the dispersal units, the seeds and pollen grains.
The term spore derives from the ancient Greek word σπορά spora, meaning "seed, sowing", related to σπόρος sporos, "sowing," and σπείρειν speirein, "to sow." In common parlance, the difference between a "spore" and a "gamete" is that a spore will germinate and develop into a sporeling, while a gamete needs to combine with another gamete to form a zygote before developing further. The main difference between spores and seeds as dispersal units is that spores are unicellular, while seeds contain within them a multicellular gametophyte that produces a developing embryo, the multicellular sporophyte of the next generation. Spores germinate to give rise to haploid gametophytes, while seeds germinate to give rise to diploid sporophytes. Vascular plant spores are always haploid. Vascular plants heterosporous. Plants that are homosporous produce spores of the same type. Heterosporous plants, such as seed plants, spikemosses and ferns of the order Salviniales produce spores of two different sizes: the larger spore in effect functioning as a "female" spore and the smaller functioning as a "male".
Such plants give rise to the two kind of spores from within separate sporangia, either a megasporangium that produces megaspores or a microsporangium that produces microspores. In flowering plants, these sporangia occur within anthers, respectively. Fungi produce spores, as a result of sexual, or asexual, reproduction. Spores are haploid and grow into mature haploid individuals through mitotic division of cells. Dikaryotic cells result from the fusion of two haploid gamete cells. Among sporogenic dikaryotic cells, karyogamy occurs to produce a diploid cell. Diploid cells undergo meiosis to produce haploid spores. Spores can be classified in several ways: In fungi and fungus-like organisms, spores are classified by the structure in which meiosis and spore production occurs. Since fungi are classified according to their spore-producing structures, these spores are characteristic of a particular taxon of the fungi. Sporangiospores: spores produced by a sporangium in many fungi such as zygomycetes.
Zygospores: spores produced by a zygosporangium, characteristic of zygomycetes. Ascospores: spores produced by an ascus, characteristic of ascomycetes. Basidiospores: spores produced by a basidium, characteristic of basidiomycetes. Aeciospores: spores produced by an aecium in some fungi such as rusts or smuts. Urediniospores: spores produced by a uredinium in some fungi such as rusts or smuts. Teliospores: spores produced by a telium in some fungi such as rusts or smuts. Oospores: spores produced by an oogonium, characteristic of oomycetes. Carpospores: spores produced by a carposporophyte, characteristic of red algae. Tetraspores: spores produced by a tetrasporophyte, characteristic of red algae. Chlamydospores: thick-walled resting spores of fungi produced to survive unfavorable conditions. Parasitic fungal spores may be classified into internal spores, which germinate within the host, external spores called environmental spores, released by the host to infest other hosts. Meiospores: spores produced by meiosis.
Examples are the precursor cells of gametophytes of seed plants found in flowers or cones, the zoospores produced from meiosis in the sporophytes of algae such as Ulva. Microspores: meiospores that give rise to a male gametophyte. Megaspores: meiospores that give rise to a female gametophyte. Mitospores: spores produced by mitosis. Fungi in which only mitospores are found are called "mitosporic fungi" or "anamorphic fungi", are classified under the taxon Deuteromycota. Spores can be differentiated by. Zoospores: mobile spores that move by means of one or more flagella, can be found in some algae and fungi. Aplanospores: immobile spores that may potentially grow flagella. Autospores: immobile spores that cannot develop flagella. Ballistospores: spores that are forcibly discharged or ejected from the fungal fruiting body as the result of an internal force, such as buildup of pressure. Most basidiospores are ballistospores, another notable e
A fern is a member of a group of vascular plants that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e. having specialized tissues that conduct water and nutrients and in having life cycles in which the sporophyte is the dominant phase. Like other vascular plants, ferns have complex leaves called megaphylls, that are more complex than the microphylls of clubmosses. Most ferns are leptosporangiate ferns, sometimes referred to as true ferns, they produce coiled fiddleheads that expand into fronds. The group includes about 10,560 known extant species. Ferns are defined here in the broad sense, being all of the Polypodiopsida, comprising both the leptosporangiate and eusporangiate ferns, the latter itself comprising ferns other than those denominated true ferns, including horsetails or scouring rushes, whisk ferns, marattioid ferns, ophioglossoid ferns. Ferns first appear in the fossil record about 360 million years ago in the late Devonian period, but many of the current families and species did not appear until 145 million years ago in the early Cretaceous, after flowering plants came to dominate many environments.
The fern Osmunda claytoniana is a paramount example of evolutionary stasis. Ferns are not of major economic importance, but some are used for food, medicine, as biofertilizer, as ornamental plants and for remediating contaminated soil, they have been the subject of research for their ability to remove some chemical pollutants from the atmosphere. Some fern species, such as bracken and water fern are significant weeds world wide; some fern genera, such as Azolla can fix nitrogen and make a significant input to the nitrogen nutrition of rice paddies. They play certain roles in mythology and art. Like the sporophytes of seed plants, those of ferns consist of stems and roots. Stems: Fern stems are referred to as rhizomes though they grow underground only in some of the species. Epiphytic species and many of the terrestrial ones have above-ground creeping stolons, many groups have above-ground erect semi-woody trunks; these can reach up to 20 meters tall in a few species. Leaf: The green, photosynthetic part of the plant is technically a megaphyll and in ferns, it is referred to as a frond.
New leaves expand by the unrolling of a tight spiral called a crozier or fiddlehead fern. This uncurling of the leaf is termed circinate vernation. Leaves are divided into a sporophyll. A trophophyll frond is a vegetative leaf analogous to the typical green leaves of seed plants that does not produce spores, instead only producing sugars by photosynthesis. A sporophyll frond is a fertile leaf that produces spores borne in sporangia that are clustered to form sori. In most ferns, fertile leaves are morphologically similar to the sterile ones, they photosynthesize in the same way. In some groups, the fertile leaves are much narrower than the sterile leaves, may have no green tissue at all; the anatomy of fern leaves can either be simple or divided. In tree ferns, the main stalk that connects the leaf to the stem has multiple leaflets; the leafy structures that grow from the stipe are known as pinnae and are again divided into smaller pinnules. Roots: The underground non-photosynthetic structures that take up water and nutrients from soil.
They are always fibrous and structurally are similar to the roots of seed plants. Like all other vascular plants, the diploid sporophyte is the dominant phase or generation in the life cycle; the gametophytes of ferns, are different from those of seed plants. They are free-living and resemble liverworts, whereas those of seed plants develop within the spore wall and are dependent on the parent sporophyte for their nutrition. A fern gametophyte consists of: Prothallus: A green, photosynthetic structure, one cell thick heart or kidney shaped, 3–10 mm long and 2–8 mm broad; the prothallus produces gametes by means of: Antheridia: Small spherical structures that produce flagellate sperm. Archegonia: A flask-shaped structure that produces a single egg at the bottom, reached by the sperm by swimming down the neck. Rhizoids: root-like structures that consist of single elongated cells, that absorb water and mineral salts over the whole structure. Rhizoids anchor the prothallus to the soil. Ferns first appear in the fossil record in the early Carboniferous period.
By the Triassic, the first evidence of ferns related to several modern families appeared. The great fern radiation occurred in the late Cretaceous, when many modern families of ferns first appeared. Ferns were traditionally classified in the class Filices, in a Division of the Plant Kingdom named Pteridophyta or Filicophyta. Pteridophyta is no longer recognised as a valid taxon; the ferns are referred to as Polypodiophyta or, when treated as a subdivision of Tracheophyta, although this name sometimes only refers to leptosporangiate ferns. Traditionally, all of the spore producing vascular plants were informally denominated the pteridophytes, rendering the term synonymous with ferns and fern allies; this can be confusing because members of the division Pteridophyta were denominated pteridophytes. Traditionally, three discrete groups have be
Microphylls and megaphylls
In plant anatomy and evolution a microphyll is a type of plant leaf with one single, unbranched leaf vein. Plants with microphyll leaves occur early in the fossil record, few such plants exist today. In the classical concept of a microphyll, the leaf vein emerges from the protostele without leaving a leaf gap. Leaf gaps are small areas above the node of some leaves where there is no vascular tissue, as it has all been diverted to the leaf. Megaphylls, in contrast, have multiple veins within the leaf gaps above them in the stem; the clubmosses and horsetails have microphylls, as in all extant species there is only a single vascular trace in each leaf. These leaves are narrow because the width of the blade is limited by the distance water can efficiently diffuse cell-to-cell from the central vascular strand to the margin of the leaf. Despite their name, microphylls are not always small: those of Isoëtes can reach 25 centimetres in length, the extinct Lepidodendron bore microphylls up to 78 cm long.
The enation theory of microphyll evolution posits that small outgrowths, or enations, developed from the side of early stems. Outgrowths of the protostele emerged towards the enations, continued to grow into the leaf to form the mid-vein; the fossil record appears to display these traits in this order, but this may be a coincidence, as the record is incomplete. The telome theory proposes instead that both megaphylls originated by the reduction; the simplistic evolutionary models, however, do not correspond well to evolutionary relationships. Some genera of ferns display complex leaves that are attached to the pseudostele by an outgrowth of the vascular bundle, leaving no leaf gap. Horsetails bear only a single vein, appear to be microphyllous; some gymnosperms bear needles with only one vein, but these evolved from plants with complex leaves. An interesting case is that of Psilotum, which has a protostele, enations devoid of vascular tissue; some species of Psilotum have a single vascular trace that terminates at the base of the enations.
Psilotum was long thought to be a "living fossil" related to early land plants. However, genetic analysis has shown Psilotum to be a reduced fern, it is not clear whether leaf gaps are a homologous trait of megaphyllous organisms or have evolved more than once. While the simple definitions can still be used in modern botany, the evolutionary history is harder to decipher. Vegetation classification
The Cambrian Period was the first geological period of the Paleozoic Era, of the Phanerozoic Eon. The Cambrian lasted 55.6 million years from the end of the preceding Ediacaran Period 541 million years ago to the beginning of the Ordovician Period 485.4 mya. Its subdivisions, its base, are somewhat in flux; the period was established by Adam Sedgwick, who named it after Cambria, the Latin name of Wales, where Britain's Cambrian rocks are best exposed. The Cambrian is unique in its unusually high proportion of lagerstätte sedimentary deposits, sites of exceptional preservation where "soft" parts of organisms are preserved as well as their more resistant shells; as a result, our understanding of the Cambrian biology surpasses that of some periods. The Cambrian marked a profound change in life on Earth. Complex, multicellular organisms became more common in the millions of years preceding the Cambrian, but it was not until this period that mineralized—hence fossilized—organisms became common; the rapid diversification of life forms in the Cambrian, known as the Cambrian explosion, produced the first representatives of all modern animal phyla.
Phylogenetic analysis has supported the view that during the Cambrian radiation, metazoa evolved monophyletically from a single common ancestor: flagellated colonial protists similar to modern choanoflagellates. Although diverse life forms prospered in the oceans, the land is thought to have been comparatively barren—with nothing more complex than a microbial soil crust and a few molluscs that emerged to browse on the microbial biofilm. Most of the continents were dry and rocky due to a lack of vegetation. Shallow seas flanked the margins of several continents created during the breakup of the supercontinent Pannotia; the seas were warm, polar ice was absent for much of the period. Despite the long recognition of its distinction from younger Ordovician rocks and older Precambrian rocks, it was not until 1994 that the Cambrian system/period was internationally ratified; the base of the Cambrian lies atop a complex assemblage of trace fossils known as the Treptichnus pedum assemblage. The use of Treptichnus pedum, a reference ichnofossil to mark the lower boundary of the Cambrian, is difficult since the occurrence of similar trace fossils belonging to the Treptichnids group are found well below the T. pedum in Namibia and Newfoundland, in the western USA.
The stratigraphic range of T. pedum overlaps the range of the Ediacaran fossils in Namibia, in Spain. The Cambrian Period was followed by the Ordovician Period; the Cambrian is divided into ten ages. Only three series and six stages are named and have a GSSP; because the international stratigraphic subdivision is not yet complete, many local subdivisions are still used. In some of these subdivisions the Cambrian is divided into three series with locally differing names – the Early Cambrian, Middle Cambrian and Furongian. Rocks of these epochs are referred to as belonging to Upper Cambrian. Trilobite zones allow biostratigraphic correlation in the Cambrian; each of the local series is divided into several stages. The Cambrian is divided into several regional faunal stages of which the Russian-Kazakhian system is most used in international parlance: *Most Russian paleontologists define the lower boundary of the Cambrian at the base of the Tommotian Stage, characterized by diversification and global distribution of organisms with mineral skeletons and the appearance of the first Archaeocyath bioherms.
The International Commission on Stratigraphy list the Cambrian period as beginning at 541 million years ago and ending at 485.4 million years ago. The lower boundary of the Cambrian was held to represent the first appearance of complex life, represented by trilobites; the recognition of small shelly fossils before the first trilobites, Ediacara biota earlier, led to calls for a more defined base to the Cambrian period. After decades of careful consideration, a continuous sedimentary sequence at Fortune Head, Newfoundland was settled upon as a formal base of the Cambrian period, to be correlated worldwide by the earliest appearance of Treptichnus pedum. Discovery of this fossil a few metres below the GSSP led to the refinement of this statement, it is the T. pedum ichnofossil assemblage, now formally used to correlate the base of the Cambrian. This formal designation allowed radiometric dates to be obtained from samples across the globe that corresponded to the base of the Cambrian. Early dates of 570 million years ago gained favour, though the methods used to obtain this number are now considered to be unsuitable and inaccurate.
A more precise date using modern radiometric dating yield a date of 541 ± 0.3 million years ago. The ash horizon in Oman from which this date was recovered corresponds to a marked fall in the abundance of carbon-13 that correlates to equivalent excursions elsewhere in the world, to the disappearance of distinctive Ediacaran fossils. There are arguments that the dated horizon in Oman does not correspond to the Ediacaran-Cambrian boundary, but represents a facies change from marine to evaporite-dominated strata — which w
The spermatophytes known as phanerogams or phaenogams, comprise those plants that produce seeds, hence the alternative name seed plants. They are a subset of the embryophytes or land plants; the term phanerogams or phanerogamae is derived from the Greek φανερός, phanerós meaning "visible", in contrast to the cryptogamae from Greek κρυπτός kryptós = "hidden" together with the suffix γαμέω, gameein, "to marry". These terms distinguished those plants with hidden sexual organs from those with visible sexual organs; the extant spermatophytes form five divisions, the first four of which are traditionally grouped as gymnosperms, plants that have unenclosed, "naked seeds": Cycadophyta, the cycads, a subtropical and tropical group of plants, which includes a single living species of tree in the genus Ginkgo, the conifers, which are cone-bearing trees and shrubs, Gnetophyta, the gnetophytes, various woody plants in the relict genera Ephedra and Welwitschia. The fifth extant division is the flowering plants known as angiosperms or magnoliophytes, the largest and most diverse group of spermatophytes.
Angiosperms possess seeds enclosed unlike gymnosperms. In addition to the taxa listed above, the fossil record contains evidence of many extinct taxa of seed plants; the so-called "seed ferns" were one of the earliest successful groups of land plants, forests dominated by seed ferns were prevalent in the late Paleozoic. Glossopteris was the most prominent tree genus in the ancient southern supercontinent of Gondwana during the Permian period. By the Triassic period, seed ferns had declined in ecological importance, representatives of modern gymnosperm groups were abundant and dominant through the end of the Cretaceous, when angiosperms radiated. A whole genome duplication event in the ancestor of seed plants occurred about 319 million years ago; this gave rise to a series of evolutionary changes. A middle Devonian precursor to seed plants from Belgium has been identified predating the earliest seed plants by about 20 million years. Runcaria and radially symmetrical, is an integumented megasporangium surrounded by a cupule.
The megasporangium bears an unopened distal extension protruding above the mutlilobed integument. It is suspected. Runcaria sheds new light on the sequence of character acquisition leading to the seed. Runcaria has all of the qualities of seed plants except for a solid seed coat and a system to guide the pollen to the seed. Seed-bearing plants were traditionally divided into angiosperms, or flowering plants, gymnosperms, which includes the gnetophytes, cycads and conifers. Older morphological studies believed in a close relationship between the gnetophytes and the angiosperms, in particular based on vessel elements. However, molecular studies have shown a clade of gymnosperms, with the gnetophytes in or near the conifers. For example, one common proposed set of relationships is known as the gne-pine hypothesis and looks like: However, the relationships between these groups should not be considered settled. Other classifications group all the seed plants in a single division, with classes for the five groups: Division Spermatophyta Cycadopsida, the cycads Ginkgoopsida, the ginkgo Pinopsida, the conifers, the gnetophytes Magnoliopsida, the flowering plants, or AngiospermopsidaA more modern classification ranks these groups as separate divisions: Cycadophyta, the cycads Ginkgophyta, the ginkgo Pinophyta, the conifers Gnetophyta, the gnetophytes Magnoliophyta, the flowering plantsAn alternative phylogeny of spermatophytes based on the work by Novíkov & Barabaš-Krasni 2015 with plant taxon authors from Anderson, Anderson & Cleal 2007 showing the relationship of extinct clades.
Unassigned spermatophytes: †Avatiaceae Anderson & Anderson 2003 †Axelrodiopsida Anderson & Anderson †Alexiales Anderson & Anderson 2003 †Hamshawviales Anderson & Anderson 2003 †Hexapterospermales Doweld 2001 †Hlatimbiales Anderson & Anderson 2003 †Matatiellales Anderson & Anderson 2003 †Petriellales Taylor et al. 1994 †Arberiopsida Doweld 2001 †Czekanowskiales Taylor et al. 2008 †Iraniales E. Taylor et al. 2008 †Vojnovskyales E. Taylor et al. 2008 †Hermanophytales E. Taylor et al. 2008 †Dirhopalostachyaceae E. Taylor et al. 2008