| Tetraphis pellucida | |
|---|---|
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| Tetraphis pellucida | |
Scientific classification  | |
| Kingdom: | Plantae |
| Division: | Bryophyta |
| Class: | Tetraphidopsida |
| Order: | Tetraphidales |
| Family: | Tetraphidaceae |
| Genus: | Tetraphis |
| Species: | T. pellucida |
| Binomial name | |
| Tetraphis pellucida | |
Tetraphis pellucida, the pellucid four-tooth moss, [1] is one of two species of moss in the acrocarpous genus Tetraphis. [2] Its name refers to its four large peristome teeth found on the sporophyte capsule.
Tetraphis pellucida occurs almost exclusively on rotten stumps and logs, [3] and is native to the northern hemisphere. [4] The leafy shoot is between eight and 15 mm tall. The lower leaves are 1 to 2 mm long, whereas the upper and perichaetial leaves – leaves that surround the archegonia – are 3 mm long. The leaves are plain and whole at the margins. [3]
Tetraphis pellucida reproduces both asexually through the production of gemmae, and sexually resulting in a sporophyte which will produce spores.
Tetraphis pellucida reproduces asexually through the use of propagules called gemmae. The gemmae are found either in gemma cups or stalks. Gemma cups are typically composed of three to five larger, specialized leaves, and house gemmae in the center. Stalk gemmae are found in a terminal cluster on a microphyllous stalk that extends one to four millimeters above the leafy gametophyte. [5] Gemmae are distributed largely through the energy provided by precipitation. This is possible due to the shape of gemmae cups, it allows them to harness the energy of a raindrop to propel the gemmae. Through this method it has been calculated that the average distance achieved by a gemma in a cup bearing gemmiferous shoot was 19.5 mm and 13.3 mm by a stalk gemmiferous shoot. It has been found that through disturbances gemmae found in a cup goes a distance of 12.1 mm and 16.9 mm for a stalk gemmae [5]
In environmentally controlled experiments with standard conditions (12 hours light/12 hour dark) gemmae germinated in two to four days, typically with six to eight protonemata. This growth produces a stellate structure after seven to ten days, at this time branching of the protonemata occurs. After ten days the leafy gametophyte begins to develop, either directly from the gemma or from the protonema. [6]
Tetraphis pellucida also reproduces sexually. It is a dioicous moss, having antheridia and archegonia on different gametophores. Once the archegonia is fertilized the sporophyte generation begins to form. It develops to have a seta six to 14 mm long, and have a capsule two to three mm long, with a one mm operculum. The fully developed capsule will have four peristome teeth attached to the rim of capsule. Inside the spores develop to be smooth or finely roughened and 10-13 micrometers. [3]
Due to the fact that the apical cell of Tetraphis pellucida stops dividing at an early stage of sporophyte development, much of the growth of the sporophyte is due to cell elongation and division below the apex. [7]
Whether Tetraphis pellucida as a colony exhibits asexual reproduction or sexual reproduction is determined based on shoot density. [8] At low densities (fewer than 70 shoots per cm2) there are no sporophytes and plants solely possess gemmiferous shoots. At a density of over 70 shoots/cm2, gametophores begin to appear, and by 190 shoots per cm2, there are no gemmiferous shoots. Initially archegoniophores (gametophyte shoots bearing archegonia) outnumber antheridiophores (gametophyte shoots bearing antheridia), but as the density increases further, the antheridiophores greatly outnumber the archegoniophores. [8]
Tetraphis pellucida develops a low-density asexual colony on a bare substrate, and is very susceptible to being out competed by species it commonly occurs with. Sexual colonies are much more likely to be disturbed than asexual colonies. Without disturbance Tetraphis pellucida has a very low probability of reestablishing where senescent or competitor colonies are. [9] This is shown in the fact that Tetraphis pellucida is the dominant species in gaps of bryophyte communities on logs, whereas they are a minor component in an undisturbed community. [10]
Tetraphis pellucida is characterized by having a straight, smooth surface lacking protrusions – setae – whereas Tetraphis geniculata is characterized by having a papillose or tuberculate surface in the upper portion of a sharply bent seta. Upon further examination, Tetraphis geniculata has bulging cell walls that are common in the central region of the seta, and smooth directly below the capsule; spiral torsion of the seta is also common. [11]
Alternation of generations is the type of life cycle that occurs in those plants and algae in the Archaeplastida and the Heterokontophyta that have distinct haploid sexual and diploid asexual stages. In these groups, a multicellular haploid gametophyte with n chromosomes alternates with a multicellular diploid sporophyte with 2n chromosomes, made up of n pairs. A mature sporophyte produces haploid spores by meiosis, a process which reduces the number of chromosomes to half, from 2n to n.
Bryophytes are a proposed taxonomic division containing three groups of non-vascular land plants (embryophytes): the liverworts, hornworts and mosses. They are characteristically limited in size and prefer moist habitats although they can survive in drier environments. The bryophytes consist of about 20,000 plant species. Bryophytes produce enclosed reproductive structures, but they do not produce flowers or seeds. They reproduce by spore formation. Though bryophytes were considered a paraphyletic group in recent years, almost all of the most recent phylogenetic evidence supports the monophyly of this group, as originally classified by Wilhelm Schimper in 1879. The term bryophyte comes from Ancient Greek βρύον (brúon) 'tree moss, liverwort', and φυτόν (phutón) 'plant'.
The Marchantiophyta are a division of non-vascular land plants commonly referred to as hepatics or liverworts. 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.
Fissidens adianthoides, the maidenhair pocketmoss, is a moss in the family of Fissidentaceaea. It was first collected by Hedwig in 1801.
Marchantia is a genus of liverworts in the family Marchantiaceae and the order Marchantiales.
Takakia is a genus of two species of mosses known from western North America and central and eastern Asia. The genus is placed as a separate family, order and class among the mosses. It has had a history of uncertain placement, but the discovery of sporophytes clearly of the moss-type firmly supports placement with the mosses.
Monoicy is a sexual system in haploid plants where both sperm and eggs are produced on the same gametophyte, in contrast with dioicy, where each gametophyte produces only sperm or eggs but never both. Both monoicous and dioicous gametophytes produce gametes in gametangia by mitosis rather than meiosis, so that sperm and eggs are genetically identical with their parent gametophyte.
Buxbaumia is a genus of twelve species of moss (Bryophyta). It was first named in 1742 by Albrecht von Haller and later brought into modern botanical nomenclature in 1801 by Johann Hedwig to commemorate Johann Christian Buxbaum, a German physician and botanist who discovered the moss in 1712 at the mouth of the Volga River. The moss is microscopic for most of its existence, and plants are noticeable only after they begin to produce their reproductive structures. The asymmetrical spore capsule has a distinctive shape and structure, some features of which appear to be transitional from those in primitive mosses to most modern mosses.
Plant reproduction is the production of new offspring in plants, which can be accomplished by sexual or asexual reproduction. Sexual reproduction produces offspring by the fusion of gametes, resulting in offspring genetically different from either parent. Asexual reproduction produces new individuals without the fusion of gametes. The resulting clonal plants are genetically identical to the parent plant and each other, unless mutations occur.
Cavicularia densa is the only species in the liverwort genus Cavicularia. The species was first described in 1897 by Franz Stephani, and is endemic to Japan, where it grows on fine moist soil.
The Funariidae are a widespread group of mosses in class Bryopsida. The majority of species belong to the genera Funaria and Physcomitrium.
Tetraphidaceae is a family of mosses. It includes only the two genera Tetraphis and Tetrodontium, each with two species. The defining feature of the family is the 4-toothed peristome.
Itatiella ulei is a species of moss in the family Polytrichaceae. It is the only species in the genus Itatiella. The Polytrichaceae is a common family of mosses that does not have close living relatives. Its small size and the inflexed leaf apex characterize Itatiella ulei. When this species grows directly exposed to sun at high elevations, it presents a similar aspect but can be distinguished based on the distal lamella cells which are single and rhombic.
Hypnodendron comosum, commonly known as palm moss or palm tree moss, is a ground moss which can be divided into two varieties: Hypnodendron comosum var. comosum and Hypnodendron comosum var. sieberi. Both Hypnodendron varieties most commonly grow in damp locations in the temperate and tropical rainforests of New South Wales, Victoria, and Tasmania in southern Australia and in New Zealand.
Pogonatum urnigerum is a species of moss in the family Polytrichaceae, commonly called urn haircap. The name comes from "urna" meaning "urn" and "gerere" meaning "to bear" which is believed to be a reference made towards the plant's wide-mouthed capsule. It can be found on gravelly banks or similar habitats and can be identified by the blue tinge to the overall green colour. The stem of this moss is wine red and it has rhizoids that keep the moss anchored to substrates. It is an acrocarpous moss that grows vertically with an archegonium borne at the top of each fertilized female gametophyte shoot which develops an erect sporophyte.
Climacium dendroides, also known as tree climacium moss, belongs in the order Hypnales and family Climaciaceae, in class Bryopsida and subclass Bryidae. It is identified as a "tree moss" due to its distinctive morphological features, and has four species identified across the Northern Hemisphere. The species name "dendroides" describes the tree-like morphology of the plant, and its genus name came from the structure of the perforations of peristome teeth. This plant was identified by Weber and Mohr in 1804. They often have stems that are around 2-10 cm tall and growing in the form of patches, looking like small palm-trees. They have yellow-green branches at the tip of stems. The leaves are around 2.5-3 mm long, with rounder stem leaves and pointier branch leaves. Their sporophytes are only abundant in late winter and early spring, and appears as a red-brown shoot with long stalk and cylindrical capsules.
Polytrichum strictum, commonly known as bog haircap moss or strict haircap, is an evergreen and perennial species of moss native to Sphagnum bogs and other moist habitats in temperate climates. It has a circumboreal distribution, and is also found in South America and Antarctica.
Buxbuamia viridis, also known as the green shield-moss, is a rare bryophyte found sporadically throughout the northern hemisphere. The gametophyte of this moss is not macroscopically visible; the large, distinct sporophyte of B. viridis is the only identifying structure of this moss. This moss can be found singularly or in small groups on decaying wood, mostly in humid, sub-alpine to alpine Picea abies, Abies alba, or mixed tree forests. This moss is rare and conservation efforts are being made in most countries B. viridis is found in.
Plagiomnium venustum, also known as magnificent leafy moss, is a species of moss belonging to the family Mniaceae. It is found mainly in western North America along the coastal region. This moss can be identified from other members of the Plagiomnium genus by dark coloured stomata guide cells and the absence of sterile stems. It is most commonly found growing as a mat on a variety of substrate, but mainly on humus and moist soil.
Tortula muralis, commonly known as wall screw-moss, is a species of moss in the family Pottiaceae. T. muralis is found throughout the world.