|Scientific name of the class|
|Goffinet & WRBuck|
|Scientific name of the order|
|Scientific name of the family|
The Tetraphidaceae are a family of mosses whose systematic position has long been unclear. Today they are listed as a separate class Tetraphidopsida in the Bryophytina subdivision . The species have a Holarctic distribution.
The gametophyte is very similar to that of the Bryidae . The plants are small to tiny. The leaflets are broadly oval, with or without a rib, and their lamina cells are rounded hexagonal. The stem has three-line foliage below and five-line above. Tetraphis has a central cord , tetrodontium does not. In contrast to all other deciduous mosses, the protonema forms small, club-shaped breeding organs that are used for vegetative reproduction .
The sporophyte consists of a seta with a short cylindrical, upright and symmetrical sporogon . Tetrodontium has stomata , tetraphis does not. The lid is conical and opens without an anulus. The peristome consists of only four teeth, which is what both generic names refer to. The teeth consist of a three-layer layer of numerous cells. The layer that forms the peristome remains attached to the columella .
The number of chromosomes is n = 7.
The unusual peristome and the very original number of chromosomes are the reasons that the family is now placed in a class of its own within the Bryophytina. The family contains only two genera:
Tetraphis with only two types
- Tetraphis pellucida in Europe
- Tetrodontium with only three types, all also in Europe. The plants are only one millimeter high. The protonema is persistent, so that the actual plant is reduced to a few leaves.
- Jan-Peter Frahm : Biology of Mosses. Spectrum Akademischer Verlag, Heidelberg et al. 2001, ISBN 3-8274-0164-X .
- Jan-Peter Frahm, Wolfgang Frey : Moosflora (= UTB . 1250). 4th, revised and expanded edition. Ulmer, Stuttgart 2004, ISBN 3-8252-1250-5 .