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Hornworts
Hornworts are a group of Non-vascular plant, non-vascular Embryophytes (land plants) 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. Hornworts may be found worldwide, though they tend to grow only in places that are damp or humid. Some species grow in large numbers as tiny weeds in the soil of gardens and cultivated fields. Large tropical and sub-tropical species of ''Dendroceros'' may be found growing on the bark of trees. The total number of species is still uncertain. While there are more than 300 published species names, the actual number could be as low as 100–150 species. Description Like all bryophytes, the dominant life phase of a hornwort is the h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liverworts
Liverworts are a group of non-vascular plant, non-vascular embryophyte, land plants forming the division Marchantiophyta (). They may also be referred to as hepatics. Like mosses and hornworts, they have a gametophyte-dominant life cycle, in which cells of the plant carry only a single set of genetic information. The division name was derived from the genus name ''Marchantia'', named after his father by French botanist Jean Marchant. It is estimated that there are about 9000 species of liverworts. Some of the more familiar species grow as a flattened leafless thallus, but most species are leafy with a form very much like a flattened moss. Leafy species can be distinguished from the apparently similar mosses on the basis of a number of features, including their single-celled rhizoids. Leafy liverworts also differ from most (but not all) mosses in that their leaves never have a costa (botany), costa (present in many mosses) and may bear marginal cilia (botany), cilia (very rare i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mosses
Mosses are small, non-vascular flowerless plants in the taxonomic division Bryophyta (, ) '' sensu stricto''. Bryophyta ('' sensu lato'', Schimp. 1879) may also refer to the parent group bryophytes, which comprise liverworts, mosses, and hornworts. Mosses typically form dense green clumps or mats, often in damp or shady locations. The individual plants are usually composed of simple leaves that are generally only one cell thick, attached to a stem that may be branched or unbranched and has only a limited role in conducting water and nutrients. Although some species have conducting tissues, these are generally poorly developed and structurally different from similar tissue found in vascular plants. Mosses do not have seeds and after fertilisation develop sporophytes with unbranched stalks topped with single capsules containing spores. They are typically tall, though some species are much larger. ''Dawsonia'', the tallest moss in the world, can grow to in height. There ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dendroceros
''Dendroceros'' is a genus of hornworts in the family Dendrocerotaceae.Renzaglia, Karen S. & Kevin C. Vaughn. (2000) "Anatomy, development and classification of hornworts", pages 1-20 ''in'' A. Jonathan Shaw & Bernard Goffinet (Eds.), ''Bryophyte Biology''. (Cambridge: Cambridge University Press). The genus contains about 51 species native to tropical and sub-tropical regions of the world. Description The epiphytic and epiphyllous Dendroceros is the only desiccation-tolerant hornwort genus. The gametophyte is yellowish-green and usually less than one-half cm wide. The thallus branches in a bifurcating pattern. In the subgenus ''Apoceros'', there are cavities in the central strand of the thallus. The edges of the thallus are only a single layer of cells thick and have an undulating margin. It is common to find symbiotic colonies of blue-green bacteria (usually '' Nostoc'') growing among the cells. Under a microscope, the epidermal cells have trigones. The sporophyte is e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anthoceros
''Anthoceros'' is a genus of hornworts in the family Anthocerotaceae. It is distributed globally. Species of ''Anthoceros'' are characterized by having a small to medium-sized, green thallus that is more or less lobed along the margins. Etymology The name ''Anthoceros'' means 'flower horn', referring to the characteristic horn-shaped sporophytes that all hornworts produce. Description The spores are dark gray, dark brown or black. This distinguishes it from the related genus '' Phaeoceros'', which produces yellow spores. The thallus lacks air chambers and scales, and has no well defined mid rib. It has unicellular smooth rhizoids in the ventral region. It is irregularly lobed, and exhibits rare dichotomous branching. The thallus has little to no tissue differentiation, being composed of thin, compactly arranged uniform parenchymatous cells. ''Anthoceros'' species are host to species of '' Nostoc'', a symbiotic relationship in which ''Nostoc'' provides nitrogen to its hos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megaceros
''Megaceros'' is a genus of hornworts in the family Dendrocerotaceae. The genus is found in the Old World tropics of east Asia and Australia. Its name means 'big horn', and refers both to the exceptionally large size of the gametophyte thallus and to the large, horn-shaped sporophyte that the plants produce. Many species have a branching thallus that is more than two centimeters wide. The gametophytes are monoicous. The genus ''Megaceros'' is unusual among hornworts in that the sporophyte does not have stomata, and the spores are green because they contain chloroplasts, as does the related genus ''Dendroceros ''Dendroceros'' is a genus of hornworts in the family Dendrocerotaceae.Renzaglia, Karen S. & Kevin C. Vaughn. (2000) "Anatomy, development and classification of hornworts", pages 1-20 ''in'' A. Jonathan Shaw & Bernard Goffinet (Eds.), ''Bryophy ...''. They can have as many as 14 chloroplasts per cell, the highest known number in hornworts. The elaters are helic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leiosporoceros
''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." Cladistic analysis of genetic data supports a position at the very base of the hornwort clade. 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 A mycorrhiza (; , mycorrhiza, or mycorrhizas) is a symbiotic association between a fungus and a plant. The term mycorrhiza refers to the r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Notothyladaceae
The Notothyladaceae is the only family of hornworts in the order Notothyladales. Description Plants in the Notothyladaceae grow as a solid, flattened green structure ( thallus) without internal air spaces, unlike some other hornwort families that have cavities within their tissues. Their reproductive structures include male organs ( antheridia) that develop in small chambers within the thallus, with each chamber typically containing between two and eight antheridia. The spore-producing structures may or may not have tiny pores (stomata) on their surface. The spores range in colour from yellow to blackish and often have a distinctive band (equatorial girdle) around their middle. Within the cells, the chloroplasts (structures responsible for photosynthesis) may or may not contain a central protein body called a pyrenoid. Distribution and habitat The family has a global distribution, with different genera showing distinct patterns. The genus ''Notothylas'' reaches its highest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phymatoceros
''Phymatoceros'' is the only genus in the hornwort family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ... Phymatocerotaceae and order Phymatocerotales. It includes only two species. References External links Hornwort genera {{Bryophyte-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloroplast
A chloroplast () is a type of membrane-bound organelle, organelle known as a plastid that conducts photosynthesis mostly in plant cell, plant and algae, algal cells. Chloroplasts have a high concentration of chlorophyll pigments which capture the Radiant energy, energy from sunlight and convert it to chemical energy and release oxygen. The chemical energy created is then used to make sugar and other organic molecules from carbon dioxide in a process called the Calvin cycle. Chloroplasts carry out a number of other functions, including fatty acid synthesis, amino acid synthesis, and the immune response in plants. The number of chloroplasts per cell varies from one, in some unicellular algae, up to 100 in plants like ''Arabidopsis'' and wheat. Chloroplasts are highly dynamic—they circulate and are moved around within cells. Their behavior is strongly influenced by environmental factors like light color and intensity. Chloroplasts cannot be made anew by the plant cell and must ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrenoid
Pyrenoids are sub-cellular phase-separated micro-compartments found in chloroplasts of many algae,Giordano, M., Beardall, J., & Raven, J. A. (2005). CO2 concentrating mechanisms in algae: mechanisms, environmental modulation, and evolution. ''Annu. Rev. Plant Biol.'', 56, 99-131. and in a single group of land plants, the hornworts.Villarreal, J. C., & Renner, S. S. (2012) Hornwort pyrenoids, carbon-concentrating structures, evolved and were lost at least five times during the last 100 million years. ''Proceedings of the National Academy of Sciences'',109(46), 1873-1887. 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 photosynthesis, photosynthetic enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO). Pyrenoids therefore seem to have a role analogous to that of carboxysomes in cyanobacteria. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nothoceros
''Nothoceros'' is a genus of hornworts in the family Dendrocerotaceae. The genus is found in New Zealand, South America, and neotropical and eastern North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri .... References External links Hornwort genera {{Bryophyte-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anthocerotaceae
The Anthocerotaceae is the only family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ... of hornworts in the order Anthocerotales. Anthocerotaceae is characterized by irregular or dichotomous lobing or branching, and a gametophyte lacking distinct pores. Etymology References External links Hornworts Hornwort families {{Bryophyte-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
