Wickham's striae often can be seen during microscopic examination of cutaneous lesions of lichen planus. This gives Atlantic mosses, ferns, lichen, and liverworts the chance to grow. Oral lichen planus in children is rare. This may occur in combination with other variants of lichen planus. Study shows that frequency of mucosal involvement of lichen planus patients is 30- 70%. In this treeless region, hundreds of species of grass, wildflower, moss and lichen are found. The same phycobiont species can occur in association with different fungal species as lichen partners. The same cyanobiont species can occur in association with different fungal species as lichen partners. Women with lichen sclerosus may develop vulvar carcinoma. Several rare species of Graphidion lichen depend on hazel trees. Some algae and cyanobacteria are found naturally living outside of the lichen. An example is "Reindeer moss", which is a lichen, not a moss. A single lichen may contain several algal genotypes. In lichen stage the fauna is sparse. The nunatak areas have a scarcity of flora, limited to lichen, bryophyte and algae.