Vegetation is the sum of plant life covering the ground in an area. Vegetation is a more generalised term than flora. Lithology, topography and soils all have a relationship and impact on vegetation.
Lithology is the macroscopic physical characteristics of a rock, (Thomas and Goudie, 2004). Such as the porosity, grain size and chemical composition. The lithology that lies beneath the soil has an impact on the soil in an area, both the type and amount of coverage. It also has an impact upon the saturation point of the soil and rate at which any water filtrates through the soil and the bedrock. The hardness of the lithology has an impact on the type of soil and the amount of regolith. For example if the rock type is a particularly hard rock type, such as granite and the regolith is removed, as the rock is so resistant, the material cannot be as readily replenished, visa versa for a softer rock type such as a lime stone, which is weathered much more readily. The permeability of the underlying lithology has an impact on the vegetation and the soil. In certain areas, especially across the UK, in areas around Scotland, impermeable rock can result in the water logging of the ground. These moist growing conditions encourage the growth of certain communities of vegetation which are resistant to frequent flooding of the land, such as Salix and Cornos. The lithology beneath the soils has an impact on the main component of the soil itself. The weathered material can have an impact on the Salinity, Alkalinity and Acidity of the soil.
The type of weathered material which composes the majority of the soil (not including any biota or mixing agents) has a profound relationship with the composition with the soil.
If the soil is particularly saline then only certain types of vegetation
References: Websites Unknown. (2009). vegetation and soil. Available: http://www.yourclimateyourlife.org.uk/a_soil_types.html. Last accessed 12 Aug 2010. Unknown. (2010). Top Ten Herbaceous Perennials For Chalky / Alkaline Soils. Available: http://www.findmeplants.co.uk/plants-alkaline-soils.aspx. Last accessed 12 Aug 2010. Books David S.G. Thomas and Andrew Goudie (2004). The Dictionary of Physical Geography. 3rd ed. Oxford: Blackwell Publishing.