Riccia fluitans

{{Short description|Species of liverwort}}

{{More citations needed|date=May 2021}}

{{Speciesbox

| image = RicciaFluitans1.jpg

| status = LC

| status_system = IUCN3.1

| status_ref = {{cite iucn |last1=Sergio |first1=C. |last2=Porley |first2=R.D. |year=2019 |title=Riccia fluitans (Europe assessment) |volume=2019 |page=e.T168909A88382410 |access-date=22 January 2025}}
(Europe regional assessment)

| genus = Riccia

| species = fluitans

| authority = L.

| subdivision_ranks = Varieties

| subdivision = {{Species list

|Riccia fluitans var. fluitans|

|Riccia fluitans var. reticulata|Herzog}}

| subdivision_ref = {{cite WFO |id=0001196749 |title=Riccia fluitans L. |access-date=22 January 2024}}

| synonyms = {{Species list

|hidden=yes

|Ricciella fluitans|(L.) A.Braun

|Riccardia dichotoma|Gray

|Ricciella fluitans var. hydrophila|Huebener

|Riccia eudichotoma var. fluitans|(L.) Bisch.

|Riccia fluitans var. minor|Lindenb.

|Riccia fluitans f. minor|(Lindenb.) Nees

|Riccia fluitans var. lata|Gottsche, Lindenb. & Nees

|Riccia fluitans var. nana|Grognot

|Riccia fluitans var. aquatica|T.Jensen

|Riccia canaliculata var. fluitans|(L.) Lindb.

|Riccia centrifuga|Arnell

|Ricciella minor|(Lindenb.) Trevis.

|Riccia fluitans f. lata|Underw.

|Riccia fluitans f. terrestris|Underw.

|Riccia fluitans var. pallida|Grognot ex Roum.

|Riccia fluitans var. viridescens|Roum.

|Riccia fluitans f. gracilis|Bouvet

|Riccia fluitans f. aquatica|(T.Jensen) C.E.O.Jensen

|Ricciella fluitans f. terrestris|Casares-Gil

|Ricciella fluitans var. birmensis|Lamothe

|Ricciella fluitans var. terrestris|Lamothe

|Riccia canaliculata f. fluitans|(L.) Fam.

|Fysonia tenera|Kashyap

|Riccia fluitans f. limicola|Sim

|Ricciella fluitans f. robusta|Papp

|Riccia media|Klingm.

|Riccia fluitans subf. lata|(Gottsche, Lindenb. & Nees) Kavina

|Riccia fluitans f. fluitans|

|Ricciella fluitans f. fluitans|

|Riccia fluitans subsp. fluitans|

|Ricciella fluitans var. fluitans|}}

| synonyms_ref =

}}

Riccia fluitans, the floating crystalwort,{{cite book|last=Edwards|first=Sean R.|date=2012|title=English Names for British Bryophytes|location=Wootton, Northampton|publisher=British Bryological Society|isbn=978-0-9561310-2-7|issn=0268-8034|series=British Bryological Society Special Volume|volume=5|edition=4}} is an aquatic floating plant of the liverwort genus 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.

The species epithet fluitans is Latin for floating.Archibald William Smith {{google books|ahNMkgoNJ7IC|A Gardener's Handbook of Plant Names: Their Meanings and Origins|page=140}}