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Bennettitales
Bennettitales (also known as cycadeoids) is an extinct order of seed plants that first appeared in the Permian period and became extinct in most areas toward the end of the Cretaceous. Bennettitales are among the most common Mesozoic seed plants, and had morphologies including shrub and cycad-like forms. The foliage of bennettitaleans is superficially nearly indistinguishable from that of cycads, but they are distinguished from cycads by their more complex flower-like reproductive organs, at least some of which were likely pollinated by insects. Although certainly gymnosperms (cone-bearing seed plants), the relationships of bennettitaleans to other seed plants is debated. Their general resemblance to cycads is contradicted by numerous more subtle features of their reproductive systems and leaf structure. Some authors have linked bennettitaleans to angiosperms (flowering plants) and gnetophytes (a rare and unusual group of modern gymnosperms), forming a broader group known as Anth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pterophyllum (plant)
''Pterophyllum'' is an extinct form genus of leaves known from the Carnian to the Maastrichtian, belonging to the Bennettitales (family Williamsoniaceae). It contains more than 50 species, and is mainly found in Eurasia and North America. Description ''Pterophyllum'' are characterized by their completely segmented leaves, with slender leaflets more than twice as long as they are high. The leaflets are regularly spaced, arranged opposite to each other, and have nearly parallel edges, only slightly broader at their bases and narrower at their tips. They are covered with fine longitudinal veins with minor bifurcation. The leaflets slightly lengthen towards the middle of the leaf and shrink towards its tip, for an overall lanceolate (long and tapered) or oblong shape to the leaf. At the tip of the leaf sits a terminal leaflet which can vary in shape from the rest. Like other bennettitaleans, the leaf's cuticle was syndetocheilic (with guard and subsidiary cells of the stomata havi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Williamsonia (plant)
''Williamsonia'' is a genus of plant belonging to Bennettitales, an extinct order of seed plants. Within the form classification system used in paleobotany, ''Williamsonia'' is used to refer to the female seed cones, which are associated with plants that also bore the male flower-like reproductive structure '' Weltrichia.'' Plants associated with this reproductive structure include the cycad-like ''Williamsonia sewardiana'' from the Early Cretaceous of India, as well as the woody shrub '' Kimuriella densifolia'' from the Late Jurassic of Japan. Taxonomy ''Williamsonia'' was originally described as ''Zamia gigas'' by William Crawford Williamson. William Carruthers proposed the name ''Williamsonia'' in an 1870 paper of his, with the type species being ''W. gigas''. Biology ''Williamsonia'' possessed a sturdy stem and had multiple fern-like leaves. The plant did not live in groups. The stamens of ''Williamsonia'' curved inward and upward. ''Williamsonia'' produced ovulate spor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ptilophyllum
''Ptilophyllum'' is an extinct form genus of leaves belonging to the extinct seed plant order Bennettitales. The leaves, like other Bennettitales morphogenera are generally pinnate Pinnation (also called pennation) is the arrangement of feather-like or multi-divided features arising from both sides of a common axis. Pinnation occurs in biological morphology, in crystals, such as some forms of ice or metal crystals, and in .... Leaves possibly attributable to the genus are known from the Oligocene of Australia, which may be the last known representatives of the order. References Prehistoric plant genera Bennettitales Triassic plants Jurassic plants Cretaceous plants Fossil taxa described in 1840 Prehistoric plants of North America {{cretaceous-plant-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nilssoniopteris
''Nilssoniopteris'' is an extinct form genus of leaves belonging to the Bennettitales. Leaves are slender and often entire-margined (smooth-edged), though some species have dissected leaves with numerous small segments extending down to the rachis of the leaf. ''Nilssoniopteris''-like leaves are distinguished by their syndetocheilic stomata, indicating bennettitalean affinities. Similar "taeniopterid" leaves are placed in the genus '' Nilssonia'' if their stomata are instead haplocheilic (indicating cycad affinities), or '' Taeniopteris'' if the cuticle A cuticle (), or cuticula, is any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection. Various types of "cuticle" are non- homologous, differing in their origin, structu ... is not preserved. References Prehistoric plant genera Bennettitales Permian plants Triassic plants Jurassic plants Cretaceous plants Prehistoric plants of North Ameri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gnetophyta
Gnetophyta () is a division of plants (alternatively considered the subclass Gnetidae or order Gnetales), grouped within the gymnosperms (which also includes conifers, cycads, and ginkgos), that consists of some 70 species across the three relict genera: ''Gnetum'' (family Gnetaceae), ''Welwitschia'' (family Welwitschiaceae), and ''Ephedra'' (family Ephedraceae). Fossilized pollen attributed to a close relative of ''Ephedra'' has been dated as far back as the Early Cretaceous. Though diverse in the Early Cretaceous, only three families, each containing a single genus, are still alive today. The primary difference between gnetophytes and other gymnosperms is the presence of vessel elements, a system of conduits that transport water within the plant, similar to those found in flowering plants. Because of this, gnetophytes were once thought to be the closest gymnosperm relatives to flowering plants, but more recent molecular studies have brought this hypothesis into question. Thou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cycad
Cycads are seed plants that typically have a stout and woody (ligneous) trunk (botany), trunk with a crown (botany), crown of large, hard, stiff, evergreen and (usually) pinnate leaves. The species are dioecious, that is, individual plants of a species are either male or female. Cycads vary in size from having trunks only a few centimeters to several meters tall. They typically grow very slowly and live very long. Because of their superficial resemblance, they are sometimes mistaken for Arecaceae, palms or ferns, but they are not closely related to either group. Cycads are gymnosperms (naked-seeded), meaning their fertilization, unfertilized seeds are open to the air to be directly fertilized by pollination, as contrasted with angiosperms, which have enclosed seeds with more complex fertilization arrangements. Cycads have very specialized pollinators, usually a specific species of beetle. Both male and female cycads bear cones (strobilus, strobili), somewhat similar to conife ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Williamsoniaceae
''Williamsoniaceae'' is a family within the Bennettitales, an extinct group of seed plants within the Cycadophyta subdivision. Members of this family are believed to have been around two meters tall and with widely serrate leaves along a central stem. Reproductive organs of the Williamsoniaceae have varied widely in the fossil record but almost all have been found to be borne on stalks emerging from a ring of leaves. Reproduction This family is different from Cycadeoidaceae by having the presence of cones leaving the major axis and lateral branches associated with a long peduncle covered by bracts. Some of this family reproduce by sporangia and others only produce ovule or pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophyt ... sacs. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spermatophyte
A spermatophyte (; ), also known as phanerogam (taxon Phanerogamae) or phaenogam (taxon Phaenogamae), is any plant that produces seeds, hence the alternative name seed plant. Spermatophytes are a subset of the embryophytes or land plants. They include most familiar types of plants, including all flowers and most trees, but exclude some other types of plants such as ferns, mosses, algae. The term ''phanerogams'' or ''phanerogamae'' is derived from the Greek (), meaning "visible", in contrast to the cryptogamae (), together with the suffix (), meaning "to marry". These terms distinguished those plants with hidden sexual organs (cryptogamae) from those with visible sexual organs (phanerogamae). Description 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, * Ginkgophyta, which includes a single living s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cycadeoidaceae
Cycadeoidaceae is a family of bennettitalean plants which flourished in the Mesozoic era. Two genera, ''Cycadeoidea'' and ''Monanthesia'', are currently recognised though most species are poorly known. They had a similar morphology to cycads Cycads are seed plants that typically have a stout and woody (ligneous) trunk with a crown of large, hard, stiff, evergreen and (usually) pinnate leaves. The species are dioecious, that is, individual plants of a species are either male or ..., with thick, branchless trunks covered in scale leaves. References Bennettitales Jurassic plants Cretaceous plants Prehistoric plant families Jurassic first appearances Cretaceous extinctions {{cretaceous-plant-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anthophyta
The anthophytes are a grouping of plant taxa bearing flower-like reproductive structures. They were formerly thought to be a clade comprising plants bearing flower-like structures. The group contained the angiosperms - the extant flowering plants, such as roses and grasses - as well as the Gnetales and the extinct Bennettitales. Detailed morphological and molecular studies have shown that the group is not actually monophyletic, with proposed floral homologies of the gnetophytes and the angiosperms having evolved in parallel. This makes it easier to reconcile molecular clock data that suggests that the angiosperms diverged from the gymnosperms around 320-300 mya. Some more recent studies have used the word anthophyte to describe a group which includes the angiosperms and a variety of fossils ( glossopterids, ''Pentoxylon'', Bennettitales, and ''Caytonia ''Caytonia'' is an extinct genus of seed ferns. Description ''Caytonia'' has berry like cupules with numerous sma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gymnosperm
The gymnosperms ( lit. revealed seeds) are a group of seed-producing plants that includes conifers, cycads, ''Ginkgo'', and gnetophytes, forming the clade Gymnospermae. The term ''gymnosperm'' comes from the composite word in el, γυμνόσπερμος ( el, γυμνός, translit=gymnos, lit=naked, label=none and el, σπέρμα, translit=sperma, lit=seed, label=none), literally meaning 'naked seeds'. The name is based on the unenclosed condition of their seeds (called ovules in their unfertilized state). The non-encased condition of their seeds contrasts with the seeds and ovules of flowering plants (angiosperms), which are enclosed within an ovary. Gymnosperm seeds develop either on the surface of scales or leaves, which are often modified to form cones, or solitary as in yew, ''Torreya'', ''Ginkgo''. Gymnosperm lifecycles involve alternation of generations. They have a dominant diploid sporophyte phase and a reduced haploid gametophyte phase which is dependent on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thérèse Ekblom
Thérèse Ekblom (1867-1941) was a Swedish botanical and zoological illustrator. She often collaborated with her husband, Axel Richard Ekblom (1858-1914). Ekblom was born Lovisa Teresia Jansson, in Stockholm, Sweden, to a family of artists. Her father and brothers were scene painters at the Royal Swedish Opera. Ekblom attended the Academy of Art in Stockholm, where she met her husband. They married in 1895 and had five children. While pursuing their studies, the Ekbloms worked with Veit Brecher Wittrock, Professor at the Bergius Botanic Garden. They painted watercolors of species that Professor Wittrock was investigating. From the 1890s, the Ekbloms worked in various departments at the Swedish Museum of Natural History and for botanists at the botanical garden. After the death of artist Carl Axel Hedelin in 1894, Ekblom succeeded him to work on a project creating pencil illustrations of plant fossils from Iceland being studied by paleobotanist Alfred Gabriel Nathorst. She worked ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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