Polytrichaceae

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Polytrichaceae
Beautiful Widertonmoos (Polytrichum formosum)

Beautiful Widertonmoos ( Polytrichum formosum )

Systematics
Empire : Plants (Plantae)
Department : Moss (Bryophyta)
Subdivision : Bryophytina
Class : Polytrichopsida
Order : Polytrichales
Family : Polytrichaceae
Scientific name of the  class
Polytrichopsida
Doweld
Scientific name of the  order
Polytrichales
M. meat.
Scientific name of the  family
Polytrichaceae
Schwägr.

The Polytrichaceae or Maidenhair Moss are a family of the moss . They alone form the class Polytrichopsida . Among the mosses one finds the strongest differentiation of different tissues: In the middle of the trunk runs a water-conducting central strand, similar to that found in the ancestors of the ferns . The Polytrichaceae are therefore also considered to be a relatively original representative of the mosses. The central strand makes a very high growth of the representatives of this family possible.

There are other German names for the family: "Haarmützenmoose", "Bürstenmoose" or "Widertonmoose". The first two names refer to the kalyptra , a hood on the capsule, which in this family often consists of light brown felted hair.

features

Gametophyte

The Polytrichaceae have the most highly developed gametophytes among the mosses. They are upright, usually quite strong mosses that usually grow on earth in loose lawns. Some of the most conspicuous mosses in European forests as well as the largest mosses belong to this group. The upright stems are usually simple, rarely forked or tufted. They have a central strand (hadrom) of water-conducting cells (hydroids), around which a hollow cylinder of assimilate- conducting cells ( leptome ) lies. The two parts thus correspond to a protostele , i.e. i. a concentric vascular bundle with inner xylem . The structure of the stem resembles that of the cormophytes ; However, here it is the gametophyte, in the case of the cormophytes, the sporophyte, which has this structure.

The leaflets have a rib in which there are water- and assimilate-conducting cells as well as strengthening elements. On the ventral side there are longitudinal lamellae, the cells of which are used for water storage and photosynthesis . The end cells of the lamellae often have a specific shape.

Due to their anatomy and the well-developed conduction tissue, feminine hair mosses include the largest mosses. The Polytrichum commune , which is also native to Central Europe , reaches a height of 50 centimeters, as does the Australasian Dawsonia superba .

The antheridia stands in the plants of this family are often surrounded by differentiated bracts, so that it appears that the mosses are developing flowers.

Sporophyte

The sporophyte is built significantly differently than in the Bryidae, to which the Polytrichales were previously placed. The structure of the peristome in particular is unique among mosses: it consists of concentric layers of whole cells, while in the Bryidae it consists of remnants of cell walls. The peristome has 32 or 64 teeth in a row. The kalyptra is shaped like a cap or bonnet and is bare or more often hairy. The German name Frauenhaarmoos refers to this hair. The opening of the capsule is still closed by a pale skin (epiphragma) after the lid has fallen off.

distribution

The Polytrichaceae occur mainly in the temperate and cold zones of both hemispheres up to the Arctic and Antarctic . In the tropics, most species are found in the mountains.

Systematics

The family consists of 18 genera with around 220 species:

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. 142-145.

Web links

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