<Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (July 2017) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (July 2017) (Learn how and when to remove this template message) </Td> </Tr> <P> Xerosere is a plant succession that is limited by water availability . It includes the different stages in a xerarch succession . Xerarch succession of ecological communities originated in extremely dry situation such as sand deserts, sand dunes, salt deserts, rock deserts etc . A xerosere may include lithoseres (on rock) and psammoseres (on sand). </P> <P> Bare rocks are produced when glaciers recede or volcanoes erupt . Erosion of these rocks is brought by rain water and wind loaded with soil particles . The rain water combines with atmospheric carbon dioxide that corrodes the surface of the rocks and produce crevices . Water enters these crevices, freezes and expands to separate boulders . These boulders move down under the influence of gravity and wear particles from the rocks . Also when the wind loaded with soil particles strikes against the rocks, it removes soil particles . All these processes lead to formation of a little soil at the surface of these bare rocks . Animals such as spiders which can hide between boulders or stones invade these rocks . These animals live by feeding on insects which have been blown in or flown in . Algal and fungal spores reach these rocks by air from the surrounding areas . These spores grow and form symbiotic association, the lichen, which act as pioneer species of bare rocks . The process of succession starts when autotrophic organisms start living in the rocks . </P>

Which of the following lichen are the pioneer in xerosere