Submerged star liver moss

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Submerged star liver moss
Submerged star liver moss (Riccia fluitans), submerged form

Submerged star liver moss ( Riccia fluitans ), submerged form

Systematics
Class : Marchantiopsida
Subclass : Marchantiidae
Order : Ricciales
Family : Ricciaceae
Genre : Riccia
Type : Submerged star liver moss
Scientific name
Riccia fluitans
L. emend. Lorb.

The submerged star liver moss ( Riccia fluitans ), also known as (flooding) pond liver moss , is a liverwort that floats or occurs submerged in the water . In autumn it sinks to the bottom of the water. New individuals develop from the enduring Thallusspitzen in spring. The dioecious liverwort is extremely rarely fruiting, so that reproduction takes place almost exclusively through sprouting . As a collective species ( Riccia fluitans agg. ) The taxon includes Riccia fluitans s. st. also Riccia rhenana Lorb. ex trash. Frib. This taxonomically controversial clan can only be delimited in terms of the land form and the number of chromosomes and is therefore often not considered separately from Riccia fluitans .

description

Close up of a thallus tip
Loosely floating thalli of the pond liver moss, here between the small duckweed
Landform on limous sand

This liverwort does not form rhizoids (root felt). Its bearings (thalli) are light green, ribbon-shaped, irregularly forked several times and up to 4 cm long. The bearings of the floating form are narrow band-shaped and 1 to 1.2 mm wide. The land form is coarse, less forked and the thalli can be up to 2.8 mm wide - this value is only achieved by the taxon R. rhenana , while the terrestrial form of R. fluitans s. st. only has thalli up to 1.5 (1.8) mm wide. The ends of the thallus are rounded, somewhat widened, provided with one or two incisions and with underlying, transparent air chambers that have a network-like field ( aerenchyma ). Breathing openings are not uncommon. There are only a few colorless, crescent-shaped abdominal scales along the center line (compare, however, the swimming liver moss ).

The submerged star liver moss can survive dehydration for over six months ( poikilohydric ) and sprouts again after about one to two weeks after watering. A culture is even possible from younger herbarium material .

Distribution and location

The submerged star liver moss is widespread worldwide and mostly inhabits shallow, sunny to shady, meso- to weakly eutrophic, weakly acidic to lime-rich or base-rich and clean standing water or slow-flowing ditches. The swimming form floats under water (submerged) or just above the water surface. Less landforms grow on dry mud. Spongy, spherical cushions are sometimes formed when submerged. The species or group of species often occurs together with duckweed plants of the genera Lemna , Spirodela or Wolffia and is sometimes displaced by them when there is increased nutrient availability.

use

This moss is widely used in aquaristics - as a spawning substrate for fish and as an ornamental plant.

literature

Individual evidence

  1. ↑ Michael Sauer (arr.): Ricciaceae, Sternlebermoose. In: Martin Nebel & Georg Philippi (eds.): Die Moose Baden-Württembergs. Volume 3: Special Part (Bryophyta: Sphagnopsida, Marchantiophyta, Anthocerotophyta). Ulmer, Stuttgart 2005, p. 114 ff. ISBN 3-8001-3278-8
  2. ↑ Christel Kasselmann : aquarium plants. Ulmer Verlag, Stuttgart 1995; 2nd, revised and expanded edition 1999, ISBN 3-8001-7454-5 , p. 404.

Web links

Commons : Riccia fluitans  - album with pictures, videos and audio files