Many different features may be called upon in the identification of lichens.
Colour and shape, whether shrubby, leafy or crustose, are the most basic observations [Figure 7: Parmelia & Ramalina; Figure 8: Placopsis lambii].
The presence or absence of any one of a variety of small-scale structures is often important for identification too [Figure 9: Parmelia sulcata with apothecia (fruiting bodies); Figure 10: Cladonia spp, Murlough].
Some lichens cannot be identified on gross morphological characters alone. Microsopic examination of spores or other structures may be necessary to separate otherwise similar types.
Simple chemical tests may also be helpful. Applying a drop of potassium hydroxide or sodium hypochlorite (bleach) may produce a distinctive colour change. But for some lichens the chemical differences can only be teased out using chromatography.