Star liver moss

Star liver moss
Riccia Huebeneriana
Systematics
Department : Liverworts (Marchantiophyta) Class : Marchantiopsida Subclass : Marchantiidae Order : Ricciales Family : Ricciaceae Genre : Star liver moss
Scientific name
Riccia
L.

Rhizoids

The star liver mosses ( Riccia L.) are a genus within the order Marchantiales . Worldwide over 150 species belong to the genus, the distribution center of which is in areas with a Mediterranean climate. The European representatives can be divided into the two sub-genera Ricciella (with air chambers) and Riccia based on the appearance of air chambers.

description

Ricci are small liverworts that live on earth or in water , among which there are both annual and perennial species. The thallus consists of multiple dichotomously branched segments, which leads to the development of the characteristic rosette or semi-rosette shape. Papillae or cilia are sometimes formed at the edges .
The tissue can either consist of a loosely organized assimilation tissue under a mostly interrupted epidermis , or it is formed from a contiguous epidermis with underlying compact rows of cells without further differentiation. All species of the genus lack the oil bodies that are otherwise characteristic of many liverworts . The antheridia and archegonia lie scattered and sunk into the thallus . The mature spores are only released when the thallus disintegrates. 32–1350 spores with a diameter of 40 to 200 µm are produced per capsule. In some species, the number and size of the air chambers on the surface of the spores is a key determinant.

distribution

The genus is cosmopolitan. Their main distribution is in areas with a Mediterranean climate, where the diversity center of the genus is located. The alternation of dry and wet periods is essential for the appearance of the genus. The genus is therefore absent in tropical areas without dry seasons.

ecology

Riccia species grow mainly on open-ground locations with a mineral subsoil. Soils with a very good water holding capacity, such as clay and loam soils, are preferably populated. Almost all species are relatively weak, pioneer species that are dependent on regular disturbance. Such conditions are common on man-made sites such as B. fields or periodically dry falling small bodies of water to be found. Others, such as Riccia cavernosa , occur on regularly flooded floodplain floors along rivers.
In areas with semi-arid and arid conditions, the ecology of the star liverwort that occurs there changes significantly. The species are mostly persistent and no longer annual and have adaptations to dehydration and heat. Essential characteristics are often strongly pigmented thalli against the high radiation intensity, the curling of the thalli when dry, as well as the ability to survive for years in a dry state. In such areas, species of the genus Riccia are associated with other liverworts, lichens and algae and together with them form biological crusts that play an essential role in reducing erosion.
In Central Europe, the species occur mainly in pond bottom and stubble field communities. Species of the genus in a liver moss-rich expression of the association Pottietum truncatae Waldheim 1944 can be found on slightly acidic to sub-neutral, damp stubble fields. In more oceanic climates, a society with Riccia sorocarpa , Entosthodon fascicularis and partly Sphaerocarpos species (Riccio sorocarpae-Funarietum fascicularis Lec. 1978) can be found. The Riccio cavernosae-Pseudephemeretum nitidi All in particular is found on pond floors. ex v. Pretty Distributed in 1957.

Types (selection)

Riccia cavernosa on the banks of the Rhine near Bonn

The genus can be divided into five sub-genera, of which the sub-genera Riccia and Ricciella are represented in Central Europe. Their Central European representatives are listed below.

• Subgenus Riccia with compact, undifferentiated tissue
  • Riccia ciliifera
  • Riccia gougetiana
  • Riccia michelii
  • Riccia ciliata
  • Riccia intumescens
  • Riccia sorocarpa
  • Riccia papillosa
  • Riccia beyrichiana
  • Riccia glauca
  • Riccia bifurca
  • Riccia gothica
  • Riccia subbifurca
  • Riccia trabutiana
  • Riccia warnstorfii
  • Riccia ligula
  • Riccia crozalsii
  • Riccia crustata
  • Riccia lamellosa
  • Riccia melitensis
  • Riccia macrocarpa
  • Riccia Sommieri
  • Riccia breidleri
  • Riccia bicarinata
  • Riccia atromarginata
• Subgenus Ricciella with chambered assimilation tissue
  • Riccia canaliculata
  • Riccia cavernosa
  • Riccia duplex
  • Riccia fluitans
  • Riccia Huebeneriana
  • Riccia rhenana
  • Riccia frostii
  • Riccia crystallina
  • Riccia perennis
• Subgenus Thallocarpus
• Subgenus Viridisquamata
• Subgenus Leptoriccia

Sources and further information

Individual evidence

1. ^ Matthias Ahrens: The moss vegetation of the northern Lake Constance area . In: Dissertationes botanicae Vol. 190, 1992, ISSN  0070-6728 , 681 pp.
2. ^ Rolf Marstaller: Syntaxonomic Conspect of the moss societies of Central Europe and neighboring areas . In: Haussknechtia Beiheft 13, 2006, ISSN  0863-6451 , 192 pp.

literature

• Helene Bischler: Systematics and Evolution of the Genera of the Marchantiales. J. Cramer, Stuttgart 1998, ISBN 3-443-62023-X .
• Suzanne Jovet-Ast : Les Riccia de la région méditerranéenne In: Cryptogamie Bryologie Lichénologie. No. 7, 1986, ISSN  0181-1576 , pp. 287-431.
• Ludwig opinion & Wiebke Schröder: Distribution atlas of the mosses of Germany. Volume 1, Regensburg 2007.
• Rudolf M. Schuster: The Hepaticae and Anthocerotaceae of North America. Volume 6, Field Museum of Natural History, Chicago 1992, ISBN 0-914-86821-7 .
• Ingo Holz & Michael Sauer: Riccia. In: Martin Nebel & Georg Philippi (eds.): Die Moose Baden-Württembergs . Volume 3, Ulmer Verlag, Stuttgart 2005, ISBN 3-8001-3278-8 .

Web links

Commons : Riccia  - collection of images, videos and audio files