Leiosporoceros | |
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Scientific classification | |
Kingdom: | Plantae |
Division: | Anthocerotophyta |
Class: | Leiosporocerotopsida Stotler & Crand.-Stotl. emend Duff |
Order: | Leiosporocerotales Hässel [1] |
Family: | Leiosporocerotaceae Hässel [2] |
Genus: | Leiosporoceros Hässel [2] |
Species: | L. dussii |
Binomial name | |
Leiosporoceros dussii (Steph.) Hässel | |
Synonyms | |
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Leiosporoceros dussii is the only species in the hornwort genus Leiosporoceros. The species is placed in a separate family, order, and class for being "genetically and morphologically distinct from all other hornwort lineages." [3] Cladistic analysis of genetic data supports a position at the very base of the hornwort clade. [4] Physical characteristics that distinguish the group include unusually small spores that are monolete and unornamented. Additionally, there are unique strands of Nostoc (cyanobacteria) that grow inside the plant parallel with its direction of growth. Unlike other hornworts with symbiotic cyanobacteria that enters through mucilage clefts, the mucilage clefts in Leiosporoceros is only present in young plants and then closes permanently once the cyanobacterial colonies have been established. Also mycorrhiza and pyrenoids are absent. [5] [6] Male plants have been found in Panama. [1]
The Ordovician fossil hornwort Casterlorum has been assigned to this family as well.
Nymphaeaceae is a family of flowering plants, commonly called water lilies. They live as rhizomatous aquatic herbs in temperate and tropical climates around the world. The family contains five genera with about 70 known species. Water lilies are rooted in soil in bodies of water, with leaves and flowers floating on or emergent from the surface. Leaves are round, with a radial notch in Nymphaea and Nuphar, but fully circular in Victoria and Euryale.
Cyanobacteria, also called Cyanobacteriota or Cyanophyta, are a phylum of gram-negative bacteria that obtain energy via photosynthesis. The name cyanobacteria refers to their color, which similarly forms the basis of cyanobacteria's common name, blue-green algae, although they are not usually scientifically classified as algae. They appear to have originated in a freshwater or terrestrial environment. Sericytochromatia, the proposed name of the paraphyletic and most basal group, is the ancestor of both the non-photosynthetic group Melainabacteria and the photosynthetic cyanobacteria, also called Oxyphotobacteria.
Desmidiales, commonly called the desmids, are an order in the Charophyta, a division of green algae in which the land plants (Embryophyta) emerged. Desmids consist of single-celled microscopic green algae. Because desmids are highly symmetrical, attractive, and come in a diversity of forms, they are popular subjects for microscopists, both amateur and professional.
Acorus is a genus of monocot flowering plants. This genus was once placed within the family Araceae (aroids), but more recent classifications place it in its own family Acoraceae and order Acorales, of which it is the sole genus of the oldest surviving line of monocots. Some older studies indicated that it was placed in a lineage, that also includes aroids (Araceae), Tofieldiaceae, and several families of aquatic monocots. However, modern phylogenetic studies demonstrate that Acorus is sister to all other monocots. Common names include calamus and sweet flag.
Pyrenoids are sub-cellular micro-compartments found in chloroplasts of many algae, and in a single group of land plants, the hornworts. Pyrenoids are associated with the operation of a carbon-concentrating mechanism (CCM). Their main function is to act as centres of carbon dioxide (CO2) fixation, by generating and maintaining a CO2 rich environment around the photosynthetic enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO). Pyrenoids therefore seem to have a role analogous to that of carboxysomes in cyanobacteria.
Hornworts are a group of non-vascular Embryophytes constituting the division Anthocerotophyta. The common name refers to the elongated horn-like structure, which is the sporophyte. As in mosses and liverworts, hornworts have a gametophyte-dominant life cycle, in which cells of the plant carry only a single set of genetic information; the flattened, green plant body of a hornwort is the gametophyte stage of the plant.
The Angiosperm Phylogeny Group (APG) is an informal international group of systematic botanists who collaborate to establish a consensus on the taxonomy of flowering plants (angiosperms) that reflects new knowledge about plant relationships discovered through phylogenetic studies.
Saxifragaceae is a family of herbaceous perennial flowering plants, within the core eudicot order Saxifragales. The taxonomy of the family has been greatly revised and the scope much reduced in the era of molecular phylogenetic analysis. The family is divided into ten clades, with about 640 known species in about 35 accepted genera. About half of these consist of a single species, but about 400 of the species are in the type genus Saxifraga. The family is predominantly distributed in the northern hemisphere, but also in the Andes in South America.
Diazotrophs are bacteria and archaea that fix gaseous nitrogen in the atmosphere into a more usable form such as ammonia.
Notothylas is a genus of hornworts in the family Notothyladaceae. The genus is found globally, but is usually overlooked. It is the smallest of all the hornworts, with a yellow-green gametophyte thallus that is seldom more than a centimeter in diameter, and usually much smaller.
The Notothyladaceae is the only family of hornworts in the order Notothyladales.
Folioceros is a genus of hornworts in the family Anthocerotaceae. The genus is common locally in the tropical and subtropical regions of Asia, growing on moist rocks, in fallow fields, and near waterfalls. It has a yellow-green gametophyte thallus that is crispy and translucent, with short branchings that are almost pinnate. Plants are usually less than a centimeter wide and 3 centimeters long. They may be monoicous or dioicous.
Viridiplantae constitute a clade of eukaryotic organisms that comprises approximately 450,000–500,000 species that play important roles in both terrestrial and aquatic ecosystems. They include the green algae, which are primarily aquatic, and the land plants (embryophytes), which emerged from within them. Green algae traditionally excludes the land plants, rendering them a paraphyletic group. However it is accurate to think of land plants as a kind of algae. Since the realization that the embryophytes emerged from within the green algae, some authors are starting to include them. They have cells with cellulose in their cell walls, and primary chloroplasts derived from endosymbiosis with cyanobacteria that contain chlorophylls a and b and lack phycobilins. Corroborating this, a basal phagotroph archaeplastida group has been found in the Rhodelphydia.
The Archaeplastida are a major group of eukaryotes, comprising the photoautotrophic red algae (Rhodophyta), green algae, land plants, and the minor group glaucophytes. It also includes the non-photosynthetic lineage Rhodelphidia, a predatorial (eukaryotrophic) flagellate that is sister to the Rhodophyta, and probably the microscopic picozoans. The Archaeplastida have chloroplasts that are surrounded by two membranes, suggesting that they were acquired directly through a single endosymbiosis event by feeding on a cyanobacterium. All other groups which have chloroplasts, besides the amoeboid genus Paulinella, have chloroplasts surrounded by three or four membranes, suggesting they were acquired secondarily from red or green algae. Unlike red and green algae, glaucophytes have never been involved in secondary endosymbiosis events.
Zygnematophyceae is a class of green algae in the paraphylum streptophyte algae, also referred to as Charophyta, consisting of more than 4000 described species. The Zygnematophyceae are the sister clade of the land plants.
Cyanobionts are cyanobacteria that live in symbiosis with a wide range of organisms such as terrestrial or aquatic plants; as well as, algal and fungal species. They can reside within extracellular or intracellular structures of the host. In order for a cyanobacterium to successfully form a symbiotic relationship, it must be able to exchange signals with the host, overcome defense mounted by the host, be capable of hormogonia formation, chemotaxis, heterocyst formation, as well as possess adequate resilience to reside in host tissue which may present extreme conditions, such as low oxygen levels, and/or acidic mucilage. The most well-known plant-associated cyanobionts belong to the genus Nostoc. With the ability to differentiate into several cell types that have various functions, members of the genus Nostoc have the morphological plasticity, flexibility and adaptability to adjust to a wide range of environmental conditions, contributing to its high capacity to form symbiotic relationships with other organisms. Several cyanobionts involved with fungi and marine organisms also belong to the genera Richelia, Calothrix, Synechocystis, Aphanocapsa and Anabaena, as well as the species Oscillatoria spongeliae. Although there are many documented symbioses between cyanobacteria and marine organisms, little is known about the nature of many of these symbioses. The possibility of discovering more novel symbiotic relationships is apparent from preliminary microscopic observations.
The Anthocerotaceae is the only family of hornworts in the order Anthocerotales.
The Dendrocerotaceae is the only family of hornworts in the order Dendrocerotales.
Sphaerosporoceros is a genus in the hornwort family Anthocerotaceae. It includes only two species, both originally published as species of Anthoceros but since transferred to the new genus.
Casterlorum is a genus of fossil with controversial interpretation from the Middle Ordovician Douglas Lake Member of the Lenoir Limestone from Douglas Dam Tennessee The genus was named in honor of Ken Caster.