Takakia

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Takakia
Systematics
Department : Moss (Bryophyta)
Subdivision : Takakiophytina
Class : Takakiopsida
Order : Takakiales
Family : Takakiaceae
Genre : Takakia
Scientific name of the  subdivision
Takakiophytina
Stech & W. Frey
Scientific name of the  class
Takakiopsida
Stech & W. Frey
Scientific name of the  order
Takakiales
Stech & W. Frey
Scientific name of the  family
Takakiaceae
Stech & W. Frey
Scientific name of the  genus
Takakia
S. Hatt. & Inoue

The moss genus Takakia comprises two species with mainly Asian distribution and alone forms the subdivision Takakiophytina . Due to the unique combination of characteristics of the liverwort in the gametophyte and those of the deciduous moss in the sporophyte , the genus is systematically very isolated.

features

These mosses have underground stolons, trunks without rhizoids and with a central strand. The leaflets are divided into four rows of cells and stand in three rows. The plants have mucous hairs. One species does not grow with a vertex cell , but with an apical meristem .

The number of chromosomes is n = 4.

The genus has characteristics of both the mosses and the liverworts .

Liverwort characteristics

  • Central strand in the Seta
  • Hydroids in the stem
  • The leaflets are split into single rows
  • Rhizoids are absent
  • Presence of stolons
  • Mucous papillae

So most liverwort features appear in the gametophyte .

Deciduous moss characteristics

  • Poorly developed Columella
  • Cap-shaped kalyptra
  • The spores are formed according to the seta
  • The sporophyte is persistent
  • Ultrastructure of the spermatozoids
  • Development of the Antheridia
  • Development of the Sporophyte
  • Cell network of the lamina of the leaflets
  • Oil drops instead of oil bodies
  • Gametophyte-Sporophyte Connection

Most of the deciduous moss traits appear in the sporophyte.

Systematics

The genus consists of two types:

The systematic position of the genus has not yet been conclusively clarified. One reason is that the genus was first described in 1951 using a sterile gametophyte. Only the discovery of Archegonium cleared the position as moss. First, the genus was placed among the Calobryales within the liverwort. Antheridia have only been known since 1988; the first sporophyte was found in 1990. Due to the fact that the capsule opens with a longitudinal slit, Takakia was then placed as a subclass to the Andreaeopsida . Today it is considered a separate subdivision Takakiophytina.

literature

Individual evidence

  1. ↑ Wolfgang Frey, Michael Stech, Eberhard Fischer: Bryophytes and Seedless Vascular Plants (= Syllabus of Plant Families. 3). 13th edition. Borntraeger, Berlin et al. 2009, ISBN 978-3-443-01063-8 , pp. 124-127.

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