taxon_rank riccia fluitans
Marchantiales is an ___MASK67___ of thallose liverworts that includes ___MASK45___ like " Marchantia polymorpha ", a widespread plant often found beside rivers , and " Lunularia cruciata ", a common and often troublesome weed in moist , temperate gardens and greenhouses . Riccia fluitans , whose common name is floating crystalwort , is an aquatic floating plant of the liverwort ___MASK75___ Riccia which is popular among aquarists as a retreat for young fry and is used in live - bearing tanks . It can be found floating in ponds , and often forms thick mats on and under the water surface . It normally grows quickly at the surface . When kept about two to three inches below an ordinary fluorescent bulb or in a pond exposed to full sunlight , it will form dense , bright green mats . Any single branch or antler bud can reproduce into a large colony if the plant is kept in proper conditions . It normally floats , but can also be attached to underwater objects such as logs and rocks . It can be attached with plastic mesh . Floating crystalwort is generally not compatible with duckweeds , as they cover the surface of the water quite rapidly , crowding the Riccia out . It is also easily overtaken by hair algae . Riccia is a ___MASK75___ of liverworts in the ___MASK67___ Marchantiales .