Süsswassertang

Süsswassertang
Gametophyte growing in water
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Division:	Polypodiophyta
Class:	Polypodiopsida
Order:	Polypodiales
Suborder:	Polypodiineae
Family:	Lomariopsidaceae
Genus:	Lomariopsis
Species:	L. sp.
Binomial name
Lomariopsis sp.

Süsswassertang (German spelling: Süßwassertang; see ß) is a type of aquarium plant. 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, a fern gametophyte. Further, it is a species of Lomariopsis.^[1]

History[]

Süsswassertang was first discovered in the aquarium of botanist Christen Kasselmann in 2001, who then distributed it to other hobby aquarists. The wild origin is unknown. The name Süsswassertang means "freshwater seaweed" in German.^[2] It is commonly incorrectly spelled subwassertang due to the German eszett's similarity to the latin B.

In 2009, molecular phylogeny determined it is most closely related to and may be of the same species, but may be a new, unnamed species.^[1] Reference sources may 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. All specimens in the aquarium trade are assumed to be clones of the original plant introduced in 2001.^[3]

This plant was first mis-identified as before the analysis that determined its true status. It was formerly known as "round Pellia" or "round-leaf Pellia".^{[citation needed]}

Physical characteristics[]

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.^[1]

References[]