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Zosterophyll
The zosterophylls are a group of extinct land plants that first appeared in the Silurian period. The taxon was first established by Banks in 1968 as the subdivision Zosterophyllophytina; they have since also been treated as the division Zosterophyllophyta or Zosterophyta and the class or plesion Zosterophyllopsida or Zosteropsida. They were among the first vascular plants in the fossil record, and had a world-wide distribution. They were probably stem-group lycophytes, forming a sister group to the ancestors of the living lycophytes. By the late Silurian (late Ludlovian, about ) a diverse assemblage of species existed, examples of which have been found fossilised in what is now Bathurst Island in Arctic Canada. Morphology The stems of zosterophylls were either smooth or covered with small spines known as enations, branched dichotomously, and grew at the ends by unrolling, a process known as circinate vernation. The stems had a central vascular column in which the protox ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zosterophyllales
The zosterophylls are a group of extinct land plants that first appeared in the Silurian period. The taxon was first established by Banks in 1968 as the subdivision Zosterophyllophytina; they have since also been treated as the division Zosterophyllophyta or Zosterophyta and the class or plesion Zosterophyllopsida or Zosteropsida. They were among the first vascular plants in the fossil record, and had a world-wide distribution. They were probably stem-group lycophytes, forming a sister group to the ancestors of the living lycophytes. By the late Silurian (late Ludlovian, about ) a diverse assemblage of species existed, examples of which have been found fossilised in what is now Bathurst Island in Arctic Canada. Morphology The stems of zosterophylls were either smooth or covered with small spines known as enations, branched dichotomously, and grew at the ends by unrolling, a process known as circinate vernation. The stems had a central vascular column in which the protoxyl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lycophyte
The lycophytes, when broadly circumscribed, are a group of vascular plants that include the clubmosses. They are sometimes placed in a division Lycopodiophyta or Lycophyta or in a subdivision Lycopodiophytina. They are one of the oldest lineages of extant (living) vascular plants; the group contains extinct plants that have been dated from the Silurian (ca. 425 million years ago). Lycophytes were some of the dominating plant species of the Carboniferous period, and included the tree-like Lepidodendrales, some of which grew over in height, although extant lycophytes are relatively small plants. The scientific names and the informal English names used for this group of plants are ambiguous. For example, "Lycopodiophyta" and the shorter "Lycophyta" as well as the informal "lycophyte" may be used to include the extinct zosterophylls or to exclude them. Description Lycophytes reproduce by spores and have alternation of generations in which (like other vascular plants) the sporop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sawdoniales
The Sawdoniales are an Order (biology), order or plesion of extinct zosterophylls. The zosterophylls were among the first vascular plants in the fossil record, and share an ancestor with the Lycopodiopsida, living lycophytes. The group has been divided up in various ways. In their major Cladistics, cladistic study of early land plants, Kenrick and Crane placed most of the zosterophylls in the Sawdoniales (which they treated as a plesion). Like other zosterophylls, members of the Sawdoniales bore lateral, reniform sporangia. They branched dichotomously, and grew at the ends by unrolling (vernation, circinate vernation). Some had smooth stems, others were covered in small spines; fungal bodies have been reported in some spines. Taxonomy In 1997, Kenrick and Crane placed most of the zosterophylls in the plesion Sawdoniales, characterizing the group as having "marked bilateral symmetry". Their summary cladogram did not resolve the taxa within the Sawdoniales, other than placing ''Zos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zosterophyllum
''Zosterophyllum'' was a genus of Silurian-Devonian vascular plant, vascular land plants with naked branching axes on which usually kidney-shaped sporangia were arranged in lateral positions. It is the type genus for the group known as zosterophylls, thought to be part of the lineage from which Lycopodiopsida, modern lycophytes evolved. More than 20 species have been described. Description The diagnostic features of the genus have changed since its first description in 1892, as the original species (''Zosterophyllum myretonianum'') has become better known, and as other species have been discovered. ''Zosterophyllum'' is a vascular plant. The axes (stems) are naked, lacking leaves or outgrowths ("enations"). When branching occurs, the branches are either isotomous (equally sized) or pseudomonopodial (one branch is larger than the other but still clearly involves division of the original axis rather a distinct side growth). The Sporangium, sporangia are upright on short stalks. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barinophyte
The barinophytes are a group of extinct vascular plants (tracheophytes). Their relationship with other vascular plants is unclear. They have been treated as the separate class Barinophytopsida, the order Barinophytales of uncertain class and as a family or clade Barinophytaceae within the zosterophylls. They have also been considered to be possible lycopodiopsids. Description '' Barinophyton'' is the type genus of the group; '' Protobarinophyton'' is similar. They were vascular plants with an exarch protostele. Plants consisted of alternatively arranged branches, apparently without leaves or enations, with their sporangia arranged in two rows on one-sided spike-like structures that developed on side shoots. Each sporangium was born on a curved bract-like appendage (a "sporangiferous appendage") and contained several thousand microspores, about 30–40 μm in diameter and about 30 megaspores, 410–560 μm in diameter, so that the plants were heterosporous. A similar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hicklingia
''Hicklingia'' is a genus of extinct plants of the Middle Devonian (around ). Compressed specimens were first described in 1923 from the Old Red Sandstone of Scotland., cited in Initially the genus was placed in the "rhyniophytes", but this group is defined as having terminal sporangia (spore-forming organs), and later work showed that the sporangia of ''Hicklingia'' were lateral rather than strictly terminal, so that it is now regarded as having affinities with the zosterophylls. Description The sporophyte had a tufted growth habit, with narrow leafless stems (axes) up to 17 cm high which branched dichotomously. Sporangia were borne on short stalks (up to 3 mm), on all sides of the stem and also terminally. There are oval scars on specimens where the stalks are presumed to have broken off. The lateral sporangia were closely adpressed to the stem. The effect is of a 'spike' of sporangia which terminates some stems. The sporangia opened via slits, but these did not ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sawdonia Ornata
Sawdonia is an extinct genus of early vascular plants, known from the Upper Silurian to the Lower Carboniferous (). ''Sawdonia'' is best recognized by the large number of spikes ( enations) covering the plant. These are vascular plants that do not have vascular systems in their enations. The first species of this genus (''Sawdonia ornata'') was described in 1859 by Sir J. William Dawson and, was originally attributed to the genus ''Psilophyton''. He named this plant ''Psilophyton princeps''. In 1971 Francis Hueber proposed a new genus for this species due to its "Divergent technical characters from the generic description for ''Psilophyton''." The holotype used for description is Dawson Collection Number 48, pro parte, Museum Specimen Number 3243. (See Dawson 1871, Plate IX, fig 101.) Sir J. William Dawson Collection, Peter Redpath Museum, McGill University, Montreal, Quebec, Canada. Morphology These plants are described by Hueber as having monopodially branched stems, that ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Land Plants
The embryophytes () are a clade of plants, also known as Embryophyta (Plantae ''sensu strictissimo'') () or land plants. They are the most familiar group of photoautotrophs that make up the vegetation on Earth's dry lands and wetlands. Embryophytes have a common ancestor with green algae, having emerged within the Phragmoplastophyta clade of freshwater charophyte green algae as a sister taxon of Charophyceae, Coleochaetophyceae and Zygnematophyceae. Embryophytes consist of the bryophytes and the polysporangiophytes. Living embryophytes include hornworts, liverworts, mosses, lycophytes, ferns, gymnosperms and angiosperms (flowering plants). Embryophytes have diplobiontic life cycles. The embryophytes are informally called "land plants" because they thrive primarily in terrestrial habitats (despite some members having evolved secondarily to live once again in semiaquatic/ aquatic habitats), while the related green algae are primarily aquatic. Embryophytes are comple ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxonomic Rank
In biology, taxonomic rank (which some authors prefer to call nomenclatural rank because ranking is part of nomenclature rather than taxonomy proper, according to some definitions of these terms) is the relative or absolute level of a group of organisms (a ''taxon'') in a hierarchy that reflects evolutionary relationships. Thus, the most inclusive clades (such as Eukarya and Animalia) have the highest ranks, whereas the least inclusive ones (such as ''Homo sapiens'' or ''Bufo bufo'') have the lowest ranks. Ranks can be either relative and be denoted by an indented taxonomy in which the level of indentation reflects the rank, or absolute, in which various terms, such as species, genus, Family (biology), family, Order (biology), order, Class (biology), class, Phylum (biology), phylum, Kingdom (biology), kingdom, and Domain (biology), domain designate rank. This page emphasizes absolute ranks and the rank-based codes (the International Code of Zoological Nomenclature, Zoological Code, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Class (biology)
In biological classification, class () is a taxonomic rank, as well as a taxonomic unit, a taxon, in that rank. It is a group of related taxonomic orders. Other well-known ranks in descending order of size are domain, kingdom, phylum, order, family, genus, and species, with class ranking between phylum and order. History The class as a distinct rank of biological classification having its own distinctive name – and not just called a ''top-level genus'' ''(genus summum)'' – was first introduced by French botanist Joseph Pitton de Tournefort in the classification of plants that appeared in his '' Eléments de botanique'' of 1694. Insofar as a general definition of a class is available, it has historically been conceived as embracing taxa that combine a distinct ''grade'' of organization—i.e. a 'level of complexity', measured in terms of how differentiated their organ systems are into distinct regions or sub-organs—with a distinct ''type'' of construction, whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dichotomous Branching
This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary of leaf morphology. For other related terms, see Glossary of phytopathology, Glossary of lichen terms, and List of Latin and Greek words commonly used in systematic names. A B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
David P
David (; , "beloved one") was a king of ancient Israel and Judah and the third king of the United Monarchy, according to the Hebrew Bible and Old Testament. The Tel Dan stele, an Aramaic-inscribed stone erected by a king of Aram-Damascus in the late 9th/early 8th centuries BCE to commemorate a victory over two enemy kings, contains the phrase (), which is translated as " House of David" by most scholars. The Mesha Stele, erected by King Mesha of Moab in the 9th century BCE, may also refer to the "House of David", although this is disputed. According to Jewish works such as the '' Seder Olam Rabbah'', '' Seder Olam Zutta'', and ''Sefer ha-Qabbalah'' (all written over a thousand years later), David ascended the throne as the king of Judah in 885 BCE. Apart from this, all that is known of David comes from biblical literature, the historicity of which has been extensively challenged,Writing and Rewriting the Story of Solomon in Ancient Israel; by Isaac Kalimi; page 32; ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
