Aytoniaceae

Mannia pilosa

The Aytoniaceae are a family of liverworts from the order of Marchantiales with about 85 species.

Features

The thallus is dichotomously divided or forms Ventralsprosse. In multilayer assimilation tissue there are air chambers, these are divided by chlorophyll-containing cell walls; filamentous Zellsprossungen missing. The breathing holes are more or less raised and consist of two ( rarely one ) to six rings, each with 5-8 or rarely 10 cells. Are crescent-shaped to triangular- ovate, usually purple belly scales on the underside of the thallus.

The species are mostly monoecious, dioecious rare. Antheridia are disc-shaped and sit on the top ( dorsal ) of the thallus. The Archegonienstände are raised on supports, originating at the Thallusspitze or Thallusoberseite. They are little head shaped and carry on its underside the spherical spore capsules. In Sporenreife the upper part of the capsule is dropped or disintegrates irregular. Spores are 35 to 120 microns in size.

The thalli are often adapted to drought. The family is at home especially in areas with a Mediterranean climate. Some species of the genera Aster Ella and Mannia occur in arctic and alpine regions.

System

The family Aytoniaceae 5 genera with about 85 species are counted worldwide:

• Aster Ella
• Cryptomitrium
• Mannia
• Plagiochasma
• Reboulia

With the exception of Cryptomitrium all genera are represented by only one to a few species in Central Europe.