Top - Map Lichen, Rhizocarpon sp.
Left - Lungwort, Lobaria pulmonaria
Right - Rock Tripe, Umbilicaria americana
The Museum's Lichen exhibit includes many species. Lichens are air quality indicators. When they are growing on rocks they secrete small amounts of acid which dissolves the rock, turning it very slowly to soil. Lichens are one of the first plants to be found growing in a barren area.