Polytrichaceae

Beautiful Widertonmoos ( Polytrichum formosum )

The Polytrichaceae or maidenhair Moose are a family of mosses. Alone make the class Polytrichopsida. In them you will find the strongest among the mosses differentiation of various tissues: In the middle of the stems a water- conducting central strand runs, similar to the kind one finds in precursors of Farne. The Polytrichaceae also therefore apply as relatively original representatives of the Moose. The central strand makes a very high growth of the members of this family possible.

For the family, there are more German name: " hair cap moss ", " brush Moose" or " Widertonmoose ". The first two names refer to the calyptra, a cap on the capsule, which is often in this family of light brown felt-like hairs.

Features

Gametophyte

The Polytrichaceae have the most highly developed gametophytes among the mosses. There are upright, usually quite vigorous mosses that grow usually in loose turf on earth. Some of the most striking in European forests as well as the largest Moose Moose are at the moment. The upright stems are mostly simple, rarely branched dichotomously or tufted. They have a central strand ( Hadrom ) of water- conducting cells ( hydroids ), around which a hollow cylinder assimilatleitender cells is ( leptom ). The two parts thus correspond to a protostele, i.e., a concentric vascular bundles with inner xylem. The structure of the stems so the likeness of the plant body; However, it is here the gametophyte in the cormophytes the sporophyte, which has this structure.

The leaflets have a rib in which water and assimilatleitende cells as well as strengthening elements are located. On the ventral side there are longitudinal lamellae, whose cells are used for water storage and photosynthesis. The end cells of the lamellae often have artcharakteristische form.

Because of their anatomy and the well-developed conducting tissue are among the maidenhair moss the largest mosses. The home also in Central Europe Polytrichum commune reaches 50 inches of height as well as the Australasian Dawsonia superba.

The Antheridienstände are surrounded with plants of this family of often differentiated bracts, so that it appears that Moose would train flowers.

Sporophyte

The sporophyte is clearly built differently than the Bryidae to which the Polytrichales were asked earlier. In particular, the structure of the peristome is unique among mosses: It consists of concentric layers of whole cells, while it is at the Bryidae of residues of cell walls. The peristome has 32 or 64 standing in a row teeth. The hairy calyptra has the form of a cap or hat and is naked, or more frequently. This hair is the German name maidenhair moss refers. The opening of the capsule is closed after the fall of the lid at the beginning nor by a pale skin ( Epiphragma ).

Dissemination

The Polytrichaceae come mainly in the temperate and cold zones of both hemispheres prior to the Arctic or Antarctica. In the tropics, most species are found in the mountains.

System

The family consists of 18 genera with about 220 species:

• Alophosia, monotypic Alophosia azorica

• Atrichopsis compressa

• Bartramiopsis lescurii

• Hebantia rigida

• Itatiella ulei

• Meiotrichum lyallii

• Resin Armhaarmoos ( Oligotrichum hercynicum )

• Steereobryon subulirostrum