Süsswassertang
Encyclopedia
Süsswassertang is a type of aquarium
plant formerly known as "round Pellia
" or "round-leaf Pellia". It was long considered to be a liverwort
, which it strongly resembles, but in 2009, a molecular phylogenetic study
determined that it is, in fact, an fern
gametophyte
. Further, it is a species
of Lomariopsis
. It is closest to Lomariopsis lineata, but may be a new, unnamed species. Many reference sources on the web describe it as L. lineata, but its inclusion in that species has not been validly determined. Efforts to induce the plant to form a sporophyte
have failed, which may indicate status
as a new species. This plant was first mis- identified
as Pellia endiviifolia, then as Monosolenium tenerum, before the analysis that determined its true status.
The name
means "freshwater seaweed" in German.
Reproduction is by fragmentation. Pieces that break off develop into new plants.
The plant is thalloid in form
, and exhibits indeterminate growth
. It is profusely branched, and 1 cell
-layer thick. Because of its lack of morphological
characters, it has been difficult to determine its systematic position
. Gametangia
are rarely produced, but they are clearly fern-like. The archegonia have short necks and the venter (base) is partly sunk into the thallus. The antheridia are like those of polypodialean
ferns in that they consist of a basal cell, a ring cell, and a cap cell.
Aquarium
An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...
plant formerly known as "round Pellia
Pellia
Pellia is a small but widespread genus of liverworts in the cool and temperate regions of the northern hemisphere. It is classified in order Metzgeriales and is a member of the family Pelliaceae within that order....
" or "round-leaf Pellia". It was long considered to be a liverwort
Marchantiophyta
The Marchantiophyta are a division of bryophyte plants commonly referred to as hepatics or liverworts. Like other bryophytes, they have a gametophyte-dominant life cycle, in which cells of the plant carry only a single set of genetic information....
, which it strongly resembles, but in 2009, a molecular phylogenetic study
Research
Research can be defined as the scientific search for knowledge, or as any systematic investigation, to establish novel facts, solve new or existing problems, prove new ideas, or develop new theories, usually using a scientific method...
determined that it is, in fact, an fern
Fern
A fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...
gametophyte
Gametophyte
A gametophyte is the haploid, multicellular phase of plants and algae that undergo alternation of generations, with each of its cells containing only a single set of chromosomes....
. Further, it is a species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of Lomariopsis
Lomariopsis
Lomariopsis is the type genus of the family Lomariopsidaceae of the ferns.One economically important species exists only as an aquatic gametophyte form, commonly known as süsswassertang...
. It is closest to Lomariopsis lineata, but may be a new, unnamed species. Many reference sources on the web describe it as L. lineata, but its inclusion in that species has not been validly determined. Efforts to induce the plant to form a sporophyte
Sporophyte
All land plants, and some algae, have life cycles in which a haploid gametophyte generation alternates with a diploid sporophyte, the generation of a plant or algae that has a double set of chromosomes. A multicellular sporophyte generation or phase is present in the life cycle of all land plants...
have failed, which may indicate status
Taxonomic rank
In biological classification, rank is the level in a taxonomic hierarchy. Examples of taxonomic ranks are species, genus, family, and class. Each rank subsumes under it a number of less general categories...
as a new species. This plant was first mis- identified
Identification (biology)
Identification in biology is the process of assigning a pre-existing individual or class name to an individual organism. Identification of organisms to individual names may be based on individualistic natural body features Identification in biology is the process of assigning a pre-existing...
as Pellia endiviifolia, then as Monosolenium tenerum, before the analysis that determined its true status.
The name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
means "freshwater seaweed" in German.
Reproduction is by fragmentation. Pieces that break off develop into new plants.
The plant is thalloid in form
Habit (biology)
Habit, when used in the context of biology, refers to the instinctive actions of animals and the natural tendencies of plants.In zoology, this term most often refers to specific behavioral characteristics, even when directly related to physiology...
, and exhibits indeterminate growth
Indeterminate growth
In biology and especially botany, indeterminate growth refers to growth that is not terminated in contrast to determinate growth that stops once a genetically pre-determined structure has completely formed. Thus, a plant that grows and produces flowers and fruit until killed by frost or some other...
. It is profusely branched, and 1 cell
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
-layer thick. Because of its lack of morphological
Plant morphology
Plant morphology or phytomorphology is the study of the physical form and external structure of plants. This is usually considered distinct from plant anatomy, which is the study of the internal structure of plants, especially at the microscopic level...
characters, it has been difficult to determine its systematic position
Phylogenetic tree
A phylogenetic tree or evolutionary tree is a branching diagram or "tree" showing the inferred evolutionary relationships among various biological species or other entities based upon similarities and differences in their physical and/or genetic characteristics...
. Gametangia
Gametangia
A gametangium is an organ or cell in which gametes are produced that is found in many multicellular protists, algae, fungi, and the gametophytes of plants...
are rarely produced, but they are clearly fern-like. The archegonia have short necks and the venter (base) is partly sunk into the thallus. The antheridia are like those of polypodialean
Polypodiales
The order Polypodiales encompasses the major lineages of polypod ferns, which comprise more than 80% of today's fern species. They are found in many parts of the world including tropical, semitropical and temperate areas...
ferns in that they consist of a basal cell, a ring cell, and a cap cell.
External links
- Photographs: http://www.aquaesfera.es/atlas/main.php?g2_itemId=3474