Buxbaumia | |
---|---|
![]() | |
Buxbaumia viridis | |
Scientific classification ![]() | |
Kingdom: | Plantae |
Division: | Bryophyta |
Class: | Bryopsida |
Subclass: | Buxbaumiidae Doweld |
Order: | Buxbaumiales M.Fleisch. |
Family: | Buxbaumiaceae Schimp. |
Genus: | Buxbaumia Hedw., 1801 [1] |
Type species | |
Buxbaumia aphylla Hedw. | |
Species | |
See Classification |
Buxbaumia (bug moss, bug-on-a-stick, humpbacked elves, or elf-cap moss) [2] 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 [3] to commemorate Johann Christian Buxbaum, a German physician and botanist who discovered the moss in 1712 at the mouth of the Volga River. [2] 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.
Plants of Buxbaumia have a much reduced gametophyte, bearing a sporophyte that is enormous by comparison. [4] In most mosses, the gametophyte stage of the life cycle is both green and leafy, and is substantially larger than the spore-producing stage. Unlike these other mosses, the gametophyte of Buxbaumia is microscopic, colorless, stemless, and nearly leafless. [5] [6] It consists exclusively of thread-like protonemata for most of its existence, resembling a thin green-black felt on the surface where it grows. [7] The plants are dioicous, with separate plants producing the male and female organs. [8] Male plants develop only one microscopic leaf around each antheridium, [2] [5] and female plants produce just three or four tiny colorless leaves around each archegonium. [3]
Because of its small size, the gametophyte stage is not generally noticed until the stalked sporangium develops, and is locatable principally because the sporangium grows upon and above the tiny gametophyte. [6] The extremely reduced state of Buxbaumia plants raises the question of how it makes or obtains sufficient nutrition for survival. In contrast to most mosses, Buxbaumia does not produce abundant chlorophyll and is saprophytic. [5] It is possible that some of its nutritional needs are met by fungi that grow within the plant. [3] However, a recent study of the chloroplast genome in Buxbaumia [9] failed to find any reduction in selective pressure on photosynthetic genes, suggesting that they are fully functional in photosynthesis, and that the moss is not mycoheterotrophic. This is also consistent with a lack of association between its rhizoids and nearby hyphae of soil fungi. [10]
The sporophyte at maturity is between 4 and 11 mm tall. [2] The spore capsule is attached at the top of the stalk and is distinctive, [6] being asymmetric in shape and oblique in attachment. [11] As with most other Bryopsida, the opening through which the spores are released is surrounded by a double peristome (diplolepidious) formed from the cell walls of disintegrated cells. [12] The exostome (outer row) consists of 16 short articulated "teeth". Unlike most other mosses, the endostome (inner row) does not divide into teeth, but rather is a continuous pleated membrane around the capsule opening. [13] Only the genus Diphyscium has a similar peristome structure, although that genus has only 16 pleats in its endostome, in contrast to the 32 pleats in Buxbaumia. [3] [12] Diphyscium shares with Buxbaumia one other oddity of the sporophyte; the foot (stalk base) ramifies as a result of outgrowths, so much so that they may be mistaken for rhizoids. [14]
Species of Buxbaumia may be found across much of the temperate to subarctic regions of the Northern Hemisphere, as well as cooler regions of Australia and New Zealand. [6] [8] [15] [16]
The moss is an annual or biennial plant and grows in disturbed habitats or as a pioneer species. [8] [17] The plants grow on decaying wood, rock outcrops, or directly on the soil. [6] [7] They do not grow regularly or reliably at given locations, and frequently disappear from places where they have previously been found. [7] Sporophyte stages begin their development in the autumn, and are green through the winter months. [7] Spores are mature and ready for dispersal by the late spring or early summer. [6] [8] The spores are ejected from the capsule in puffs when raindrops fall upon the capsule's flattened top. [8]
The asymmetric sporophytes of Buxbaumia aphylla develop so that the opening is oriented towards the strongest source of light, usually towards the south. [8] The species often grows together with the diminutive liverwort Cephaloziella , which forms a blackish crust that is easier to spot than Buxbaumia itself. [8]
Buxbaumia is the only genus in the family Buxbaumiaceae, the order Buxbaumiales, and the subclass Buxbaumiidae. [18] It is the sister group to all other members of class Bryopsida. [19] [20] Some older classifications included the Diphysciaceae within the Buxbaumiales (or as part of the Buxbaumiaceae) because of similarities in the peristome structure, [3] [12] or placed the Buxbaumiaceae in the Tetraphidales. [21] However, recent phylogenetic studies based on genomic and transcriptomic data [22] [23] clearly support it as the sister group of all other Bryopsida.
The genus Buxbaumia includes twelve species:
genus Buxbaumia | |
The species and phylogenetic position of Buxbaumia. [18] [20] |
Because of the simplicity of its structure, Goebel interpreted Buxbaumia as a primitive moss, transitional between the algae and mosses, [5] but subsequent research suggests that it is a secondarily reduced form. [8] [20] The unusual peristome in Buxbaumia is now thought to be a transitional form between the nematodontous (cellular teeth) peristome of the Polytrichopsida and the arthrodontous (cell wall teeth) peristome of the Bryopsida. [20]
Mosses are small, non-vascular flowerless plants in the taxonomic division Bryophytasensu stricto. Bryophyta 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 0.2–10 cm (0.1–3.9 in) tall, though some species are much larger. Dawsonia, the tallest moss in the world, can grow to 50 cm (20 in) in height. There are approximately 12,000 species.
Bryophytes are a group of land plants, sometimes treated as a taxonomic division, that contains three groups of non-vascular land plants (embryophytes): the liverworts, hornworts and mosses. In the strict sense, Bryophyta consists of the mosses only. Bryophytes 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 sexually by spores and asexually by fragmentation or the production of gemmae. 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.
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.
Fissidens adianthoides, the maidenhair pocketmoss, is a moss in the family Fissidentaceae. It was first collected by Hedwig in 1801.
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.
Andreaeaceae is a family of mosses which includes two genera, Andreaea, containing about 100 species, and the genus Acroschisma. The Andreaeaceae prefer rocky habitats ranging from tropical to arctic climates, on which they form tufted colonies, typically with reddish to blackish shoots. The capsules lack the peristome mechanism and dehisce longitudinally to release the spores, resulting in a paper-lantern appearance.
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.
The Bryopsida constitute the largest class of mosses, containing 95% of all moss species. It consists of approximately 11,500 species, common throughout the whole world.
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.
The Dicranidae are a widespread and diverse subclass of mosses in class Bryopsida, with many species of dry or disturbed areas. They are distinguished by their spores; the peristome teeth are haplolepideous with a 4:2:3 formula, and an exostome is absent.
Takakia ceratophylla is one of the two species of toothless mosses in the genus Takakia, under the Takakiaceae family. This species was first described by William Mitten in 1861. Takakia ceratophylla is vulnerable and threatened by habitat loss due to human activities.
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.
Bryales is an order of mosses.
Hypnales is the botanical name of an order of Bryophyta or leafy mosses. This group is sometimes called feather mosses, referring to their freely branched stems. The order includes more than 40 families and more than 4,000 species, making them the largest order of mosses.
Splachnaceae is a family of mosses, containing around 70 species in 6 genera. Around half of those species are entomophilous, using insects to disperse their spores, a characteristic found in no other seedless land plants.
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.
Buxbaumia 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.
Polytrichastrum formosum, commonly known as the bank haircap moss, is a species of moss belonging to the family Polytrichaceae.
{{cite journal}}
: CS1 maint: DOI inactive as of January 2024 (link)