Figure 2From: Ecological characterization of soil-inhabiting and hypolithic soil crusts within the Knersvlakte, South AfricaFrequency histograms of the thickness (A), mass (B) and depth embedded in the soil (C) of colonized and uncolonized quartz stones from a quartz field in the Knersvlakte, Western Cape, South Africa. The mean values of colonized and uncolonized quartz stones were significantly different (P < 0.001) for all three parameters.Back to article page