Riccia sp. “Dwarf” probably belongs to the species complex of Riccia fluitans. The origin of this liverwort is unknown.
It has probably been known in the aquarium hobby since the 2000s. It was offered by the company Tropica (Denmark), but is currently (2014) hardly available commercially.
The dwarf crystalwort looks like a miniature version of the “normal” crystalwort, Riccia fluitans. Even under optimal growing conditions the thallus branches become at most about half a millimetre wide, and the branch length between two successive forks is between 1 and 5 mm. It forms dense, flat, round, bright light green cushions. Older cushions have a layered structure.
(For more, see “Culture” and “Design”)
Riccia sp. "Dwarf" can, like Riccia fluitans, be cultivated as a floating plant and emersed on wet substrate, but also grows very well under water, e.g. tied onto pieces of slate, and certainly looks most beautiful in this form, especially if it is strongly lit and well supplied with CO2 and nutrients. During the day many silvery oxygen bubbles then hang in the cushions. Sometimes darker green, rather translucent shoots develop submersed, as can also be observed with Riccia fluitans.
(For more see “Design”)
References and further reading:Riccia sp. "Dwarf" can be tied onto pieces of slate, e.g., and used over a large area as a carpet in the foreground. But individual scattered cushions can also look pretty and often develop by themselves from drifted thallus pieces that get caught between ground covers, mosses, wood and stones.
This dwarf liverwort is clearly finer and more filigree than "normal" crystalwort and is therefore ideal for nano tanks. Thanks to its tiny size it can help to make an aquascape appear large.
References and further reading:
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[widget=aquaticplants/riccia-sp-dwarf]Riccia sp. "Dwarf"[/widget]