Seeing is believing. This morning I photographed a lichen growing on a pvc reflective guide post next to a culvert. Lichens seem to flourish as readily on man-made as on natural surfaces. They are grouped in growth forms which describe their appearance. The most common, fruticose (shrubby), foliose (leafy) and crustose (flake-like) account for the majority of lichens that people are likely to see. It is estimated that 6% of the earth’s land surface is covered by some 20,000 known species of lichen. There are more than 3,000 Australian lichens around 15% of which are endemic.