A plant division of seed plants containing only a few members.

A first assessment of genetic variation in Welwitschia mirabilis Hook. (1/8)

Welwitschia mirabilis is a monotypic member of the family Welwitchiaceae which, along with Ephedra and Gnetum species, comprises the gymnospermous order Gnetales. While the monophyly of this order is now widely accepted, the relationship of the Gnetales to other seed plants is still contentious. Despite the unique phylogenetic position of W. mirabilis and its extraordinary physiological and anatomical adaptations, little is known about the plant's phylogeny or its current distribution in isolated locations throughout the Namib Desert. As a preliminary step in the design of an more extensive phylogeographic study, we analyzed 37 random amplified polymorphic DNA (RAPD) loci from 59 plants distributed among five sites separated by distances of 6-440 km. Cluster analysis and analysis of molecular variance (AMOVA) revealed significant levels of variation within and between populations and little evidence of inbreeding. Genetic differences between populations reflect the geographic distances separating them. Three of the populations formed discernable genetic clusters, suggesting that little gene flow occurs between populations separated by > or = 18 km. In contrast, gene flow is occurring between two populations separated by only 6 km, supporting previous observations that pollen dispersal is primarily local and that seeds are not readily wind-born over the large distances separating most W. mirabilis populations. As a working hypothesis, we propose that W. mirabilis had a continuous distribution across its current range as much as 105 million years ago, and that as a consequence of subsequent drying trends and physical disturbance, populations became progressively isolated, accounting for their current distribution.  (+info)

High levels of genetic variation exist in Aspergillus niger populations infecting Welwitschia mirabilis hook. (2/8)

Aspergillus niger is an asexual, haploid fungus which infects the seeds of Namibia's national plant, Welwitschia mirabilis, severely affecting plant viability. We used 31 randomly amplified polymorphic DNA markers to assess genetic variation among 89 A. niger isolates collected from three W. mirabilis populations in the Namib Desert. While all isolates belonged to the same vegetative compatibility group, 84% were unique genotypes, and estimates of genotypic evenness and Simpson's index of diversity approached 1.0 in the three populations. Analysis of molecular variance revealed that 78% of the total variation sampled was among isolates from individual W. mirabilis plants. Lower, but significant, amounts of variation detected among isolates from different plants (12%) and different sites (10%) also indicated some site- and plant-level genetic differentiation. Total gene diversity (H(T) = 0.264) was mostly attributable to diversity within populations (H(S) = 0.217); the relatively low level of genetic differentiation among the sites (G(ST) = 0.141) suggests that gene flow is occurring among the three distant sites. Although sexual reproduction has never been observed in this fungus, parasexuality is a well-known phenomenon in laboratory strains. We thus attribute the high levels of genetic variation to parasexuality and/or wind-facilitated gene flow from an as of yet undocumented broader host range of the fungus on other desert vegetation. Given the apparent ease of transmission, high levels of genetic diversity, and potentially broad host range, A. niger infections of W. mirabilis may be extremely difficult to control or prevent.  (+info)

Former diversity of Ephedra (Gnetales): evidence from Early Cretaceous seeds from Portugal and North America. (3/8)

BACKGROUND AND AIMS: The extant species of the seed plant group Gnetales (Ephedra, Gnetum and Welwitschia) have been considered a remnant of a much greater, now extinct, diversity due to the pronounced differences in form and ecology among the genera. Until recently, this hypothesis has not been supported by evidence from the fossil record. This paper adds to the expanding information on Gnetales from the Early Cretaceous and describes coalified seeds from Barremian-Albian localities in Portugal and USA. METHODS: The fossils were extracted from sediment samples by sieving in water. Adhering mineral matrix was removed by chemical treatment. Seeds were investigated using light and scanning electron microscopy. Morphology and anatomy of the seeds were documented and compared with those of extant species. KEY RESULTS: The fossils share characters with extant Ephedra, for example papillae on the inner surface of the seed envelope and in situ polyplicate pollen grains that shed the exine during germination. They differ from extant Ephedra seeds in morphological and anatomical details as well as in their smaller size. Two new species of Ephedra are described together with one species assigned to a new genus of Gnetales. Other Ephedra-like seeds, for which pollen and critical morphological details are currently unknown, are also present in the samples. CONCLUSIONS: These Cretaceous seeds document that key reproductive characters and pollen germination processes have remained unchanged within Ephedra for about 120 million years or more. There is sufficient variety in details of morphology to suggest that a diversity of Ephedra and Ephedra-like species were present in the Early Cretaceous flora. Their presence in Portugal and eastern North America indicates that they were widespread on the Laurasian continent. The fossil seeds are similar to seeds of Erdtmanithecales and this supports the previously suggested relationship between Erdtmanithecales and Gnetales.  (+info)

The complete plastid genome sequence of Welwitschia mirabilis: an unusually compact plastome with accelerated divergence rates. (4/8)

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A new early Cretaceous relative of Gnetales: Siphonospermum simplex gen. et sp. nov. from the Yixian formation of northeast China. (5/8)

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The position of gnetales among seed plants: overcoming pitfalls of chloroplast phylogenomics. (6/8)

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Systematic error in seed plant phylogenomics. (7/8)

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Chengia laxispicata gen. et sp. nov., a new ephedroid plant from the Early Cretaceous Yixian Formation of western Liaoning, Northeast China: evolutionary, taxonomic, and biogeographic implications. (8/8)

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Gnetophyta is a division of seed plants that includes three living genera: Gnetum, Welwitschia, and Ephedra. These plants are characterized by their vascular structure, which is similar to that of angiosperms (flowering plants) and gymnosperms (conifers and related plants). They also have specialized leaves and pollen-bearing structures. Gnetophytes are often considered to be a sister group to the angiosperms, although their exact phylogenetic relationship is still a matter of debate. Some researchers have suggested that gnetophytes may have evolved certain traits independently as a result of convergent evolution, rather than sharing a common ancestor with the angiosperms. Despite their small number of extant species, gnetophytes have a fossil record dating back to the early Mesozoic Era, making them an important group for understanding the evolutionary history of seed plants.

At issue is whether the Gnetophyta are the sister group of angiosperms, or whether they are sister to, or nested within, other ... Gnetophyta (/nɛˈtɒfɪtə, ˈnɛtoʊfaɪtə/) is a division of plants (alternatively considered the subclass Gnetidae or order Gnetales ... 2011) suggests that the Gnetophyta are a sister group to the rest of the gymnosperms, contradicting the anthophyte hypothesis, ... In general the evolutionary relationships among the seed plants still are unresolved, and the Gnetophyta have played an ...
Gnetophyta consists of three genera, Ephedra, Gnetum and Welwitschia. All three are typically dioecious, although some Ephedra ...
This plant's phylum is gnetophyta within the class gnetopsida. This plant is widely distributed, and is protected in various ...
Gnetophyta may have 2 or 3 celled pollen grains depending on the species, and Coniferophyta pollen grains vary greatly ranging ... In some Gnetophyta species, the germ cell will release two sperm nuclei that undergo a rare gymnosperm double fertilization ... In select Gnetophyta, the female gametophyte stays singled celled. Mitosis does occur, but no cell divisions are ever made. ... This results in the mature female gametophyte in some Gnetophyta having many free nuclei in one cell. Once mature, this single ...
E. coryi is a Gymnosperm and a member of the Gnetophyta. E. coryi is a perennial shrub. Plant height ranges from 1-3 ft. The ...
... is a genus of gymnosperms, the sole genus in the family Gnetaceae within the Gnetophyta. They are tropical evergreen ... a trait they seem to share with the other living members of Gnetophyta, Ephedra and Welwitschia, as well as conifers. There are ...
Gnetophyta) in Papua New Guinea". Mycorrhiza. 22 (8): 663-8. doi:10.1007/s00572-012-0458-7. PMID 22892664. S2CID 14575220. ...
The vascular tissue contains vessel elements and in at least some taxa resembles that of the Gnetophyta. They had a cuticle ...
Gnetophyta, and Ginkgophyta: characteristics of early seed plants". Canadian Journal of Botany. 80 (9): 954-961. doi:10.1139/ ...
Gnetophyta, and Ginkgophyta: characteristics of early seed plants". Canadian Journal of Botany. 80 (9): 954-961. doi:10.1139/ ...
Gnetophyta, and Ginkgophyta: characteristics of early seed plants". Canadian Journal of Botany. 80 (9): 954-961. doi:10.1139/ ... Multiple studies also indicate that the Gnetophyta belong within the conifers despite their distinct appearances, either ...
Gnetophyta 3, 100) Pinidae (Pinophyta, conifers 70, 600) The term Pinophyta has also been used to include all conifers, extinct ... and particularly the placement of Gnetophyta. The latter have been variously classified as basal to all gymnosperms, sister ...
Sperm cells of Pinophyta and Gnetophyta are without flagella, and are carried by the pollen tube, while those of Cycadophyta ...
Yet, in Gnetophyta, there are features more similar to angiosperm pollen tubes where the tube reaches the egg with an early ... In other phyla of gymnosperms, the Coniferophyta and Gnetophyta, the sperm is non motile, and the pollen tube delivers the ...
... and one of the three living members of the division Gnetophyta alongside Gnetum and Welwitschia. In temperate climates, most ...
... is a family of gymnosperms belonging to Gnetophyta, it contains only a single extant genus, Ephedra, as well as a ...
The gymnosperms are subdivided into five Divisions, four of which, the Cycadophyta, Ginkgophyta, Gnetophyta, and Pinophyta ( ...
... is the only living genus of the family Welwitschiaceae and order Welwitschiales in the division Gnetophyta, and is ... one of three living genera in Gnetophyta, alongside Gnetum and Ephedra. Informal sources commonly refer to the plant as a " ...
... from the gymnospermous Gnetophyta and, hence, two separate evolutionary lineages within the flowering plants. Many of Hagerup's ...
Multiple molecular studies indicate that in contrast to previous classifications placing it outside the conifers, Gnetophyta ...
... gnetophyta MeSH B06.388.400.344.222 - ephedra MeSH B06.388.400.344.222.500 - ephedra sinica MeSH B06.388.400.344.333 - gnetum ...
Gnetophyta (gnetophytes), and the Magnoliophyta (Angiosperms, flowering plants). The flowering plants now dominate terrestrial ...
Carlquist studied wood anatomy of the Gnetophyta and was an author of many plant taxa, including species of the carnivorous ...
Some families and genera containing liana species include: Gnetophyta Gnetum Acanthaceae Mendoncia Thunbergia, such as T. ...
Cycadophyta Ginkgophyta Gnetophyta Pinophyta (conifers) Angiosperms Dicotyledon Asteraceae (sunflower family) Cactaceae (cactus ...
Anthocerotophyta Moss Pteridophytes Lycopodiophyta Polypodiophyta Seed plants Cycadophyta Ginkgophyta Pinophyta Gnetophyta ...
Gnetophyta - Hepatophyta - Lycopodiophyta - Magnoliophyta - Ophioglossophyta - Pinophyta - Psilotophyta - Pteridophyta Regnum ...
... and Gnetophyta, the gnetophytes, various woody plants in the relict genera Ephedra, Gnetum, and Welwitschia. The fifth extant ... the conifers Gnetophyta, the gnetophytes Magnoliophyta, the flowering plants Unassigned spermatophytes: †Cordaitales † ...
... a unique member of the Gnetophyta, also known as Tumboa, with a subterranean stem of 50 cm diameter that can grow up to 30 ...
Although secondary xylem is also found in members of the gymnosperm groups Gnetophyta and Ginkgophyta and to a lesser extent in ...
At issue is whether the Gnetophyta are the sister group of angiosperms, or whether they are sister to, or nested within, other ... Gnetophyta (/nɛˈtɒfɪtə, ˈnɛtoʊfaɪtə/) is a division of plants (alternatively considered the subclass Gnetidae or order Gnetales ... 2011) suggests that the Gnetophyta are a sister group to the rest of the gymnosperms, contradicting the anthophyte hypothesis, ... In general the evolutionary relationships among the seed plants still are unresolved, and the Gnetophyta have played an ...
Genetic analysis has howe… Phylum Gnetophyta -- gnetophytes Gnetophyta comprise about three families, one of which occurs in ... INTRODUCTION TO THE GNETOPHYTA Phylum Gnetophyta, what is unique? Only gymnosperm with vessels in xylem (in addition to ... Gnetophyta DESCRIPTION of the strangest plants on earth Gnetophyta. Each of which contains haploid megaspores slender stems ... Gnetophyta (ne-TA-fa-ta) is derived from the Moluccan Malay word Gamemuand plant (phyto -φυτο).The reference is to Gamemu (the ...
Ephedraceae is a family of gymnosperms belonging to Gnetophyta, it contains only a single extant genus, Ephedra, as well as a ...
Divisione: Gnetophyta. Classe: Gnetopsida. Sottoclasse: -. Ordine: Ephedrales. Famiglia: Ephedraceae Genere: Ephedra Regni. ...
5] https://www.agric.wa.gov.au/organisms?search_string=Gnetophyta. [6] https://www.agric.wa.gov.au/organisms?search_string= ...
Ang mga Halaman (Latin: Plantae, Aleman: Pflanze, Ingles, Olandes: plant, Kastila, Portuges, Italyano: planta) ay isang malaking grupo ng mga nilikhang bagay na may buhay. Binubuo ito ng ibat ibang miyembro tulad ng mga puno, baging, damo at lumot. Ang mga luntiang halaman, na tinatawag rin bilang mga metaphyte, ay kumukuha ng enerhiya mula sa liwanag ng sa pamamagitan ng proseso ng photosynthesis. Ang photosynthesis ay bumubuo ng asukal, ang pangunahing pagkain ng mga halaman, mula sa tubig at carbon dioxide. ...
സസ്യസാമ്രാജ്യത്തിൽ (കിങ്ഡം : പ്ലാന്റേ) ഉൾപ്പെടുന്ന ബഹുകോശ യൂക്കാരിയോട്ടുകളാണ് സസ്യങ്ങൾ(അല്ലെങ്കിൽ ചെടികൾ), ഹരിതസസ്യങ്ങൾ എന്നും അറിയപ്പെടുന്നു. വൃക്ഷങ്ങൾ, ഓഷധികൾ, കുറ്റിച്ചെടികൾ, തൃണങ്ങൾ, വള്ളികൾ, പന്നലുകൾ, പായലുകൾ, ഹരിതനിറമുള്ള ആൽഗകൾ തുടങ്ങിയവ സസ്യസാമ്രാജ്യത്തിൽ ഉൾപ്പെടുന്നു. ബീജസസ്യങ്ങൾ, ബ്രയോഫൈറ്റുകൾ, പന്നൽച്ചെടികൾ, അനുഫേണുകൾ എന്നിങ്ങനെ നിർവചിക്കപ്പെട്ടിരിക്കുന്ന ...
The phyla include Pinophyta (conifers), Cycadophyta (cycads), Ginkgophyta (ginkgoes), Gnetophyta (gnetophytes), and ...
Its dioecious (male and female plants exist separately) and is classed with the order, Gnetophyta. This group is intermediate ... Namib desert, Welwitschia mirabilis, Radix Welwitschia mirabilis, Gnetophyta, two leaves, the number two, male and female, good ...
Gnetophyta, and Ginkgophyta: characteristics of early seed plants. Canadian Journal of Botany, 80(9), 954-961. Retrieved July ...
3. Ginkgophyta 4. Gnetophyta. 56. According to 2014 IUCN Red List, which of the following vertebrate classes has the largest ...
Gnetophyta-gnetophytes Ephedra. *with seeds and flowers *Anthophyta = angiospersms = flowering plants *monocots, corn, wheat, ...
Gnetophyta. Besides ginkgos, Gnetophyta is the next smallest/least diverse of the gymnosperms. With 96 species of this kind, it ...
Iron-rich particles and globoids in embryos of seeds from phyla Coniferophyta, Cycadophyta, Gnetophyta, and Ginkgophyta: ...
Division:Gnetophyta. Class: Gnetopsida. Order: Ephedrales. Genus: Ephedra. Species: E. intermedia. Synonyms:. *Ephedra ...
Gnetophyta Gnetophytes 70 [21] Magnoliophyta Flowering plants 258650 [24] The naming of plants is governed by the International ...
Gnetophyta gnetophytes 70 [8]. Magnoliophyta flowering plants 258,650 [11]. Pirsani uga Besut *Woh ...
Gnetophyta gnetophytes 70 [21] Magnoliophyta flowering plants 258,650 [35] The naming of plants is governed by the ...
Gnetophyta. This is the mapping for the Wikipedia template Bosca Sonraí Tacsanomaíochta. Find usages of this Wikipedia template ...
Commons nisqaqa multimidya kapuyninkunayuqmi kay hawa: Gnetophyta.. *. Commons nisqaqa multimidya kapuyninkunayuqmi kay hawa: ...
Division: Gnetophyta *Class: Gnetopsida *SubClass: Gnetidae *Order: Gnetales *SubOrder: *Family: Gnetaceae *SubFamily: *Tribe: ... Gnetophyta *EEB Greenhouse Holdings native to: French Guiana / Guyana / Suriname / Venezuela / Colombia / Peru / Brazil North. ...
The plant division Gnetophyta or gnetophytes consists of three genera of woody plants grouped in the gymnosperms. The living ... Gnetophyta consists of around 70 species across the three genera Gnetum , Welwitschia , and Ephedra .The gnetophytes differ ...
Gnetophyta Anthophytatae Cvjetnice Magnoliophyta Ažurirana filogenija Embryophyta zasnovana na radu Novíkov & Barabaš-Krasni ...
There are currently 652 unused creatures in my backlog. If I cant thick of anything else to add to the list I will run out of material on 22/03/2017. If you have any creatures to suggest, please let me know, details are on the contact me page. ...
Gnetophyta (Welwitschia). B6.8 Anthophyta (angiosperms). B6.9 Spermatophyta (higher plants less ferns). B6.10. ...
a. Gnetophyta b. Ginkgophyta c. Coniferophyta. d. Magnoliophyta e. Psilotophyta. d. Magnoliophyta ...
Gnetophyta (gnetophytes). *Magnoliophyta (flowering plants). Significance. Plants are essential to the lives of different ...
Gnetae (Gnetophyta),. *???? Flowering plants (Magnoliophyta), Angiospermae:. *Basal:. *Amborella - a shrub,. *Nymphaeales - ...
The Welwitschiaceae family is classified in the plant division Gnetophyta, which includes two other families: Gnetaceae, a ...

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