**3. Mosses and hepatics**

Among the species that most stand out on more consolidated areas and even on Antarctic rocks, are mosses. The group that represents the bryophytes also has some liverworts occurring, but in this text, all will be commonly called mosses. There are, therefore, Marchantiophyta, popularly called hepatics, and the representatives of the genus

*Marchantia* are those that present the largest gametophyte (**Figure 4**), although small species of other genera sometimes take very large areas. Large populations have been found recently, such as the rare *Hygrolembidium isophyllum* in Harmony Point - Nelson

**Figure 4.** *Two Marchantiophyta, the thallose* Marchantia berteroana *(above) and the leafy* Cephalozia *sp. (below).*

**69**

**Figure 6.**

**Figure 5.**

*A moss carpet moved by wind being fixed by a scientist.*

*Two large carpet of* Sanionia uncinata *associated to* Warnstorfia sarmentosa *in the wettest areas.*

*The Vegetation of the South Shetland Islands and the Climatic Change*

Island [37]. *Marchantia* is thallose, reproducing basically by direct fragmentation of the thallus or by specialized structures, the propagules, formed in receptacles such as in the figure (called conceptacles). But the group most represented in species in the area are the leafy liverworts (about 22 species). They even have a relationship with other organisms, as in the case of *Cephaloziella varians*, which is associated with a mycorrhizal

fungus *Rhizoscyphus ericae* (ericoid symbiosis) throughout Antarctica [38–40].

Many species of liverworts are associated with dominant species in the plant community, and this reflects an interdependence. If the dominant species are threatened, by climate change, for example, their dependents will also be [41]. Bryophyta, or mosses themselves, have so far collected 113 species, within 55 genera and 17 families [18, 42]. The mosses present two main forms of growth: the pleurocarpic, where the moss stalk is prostrate, forming continuous carpets and in general covering more extensive areas if they are available (**Figures 5** and **6**);

*DOI: http://dx.doi.org/10.5772/intechopen.94269*
