Lichen is an unusual growth, a combination of fungus and algae. If you find this hard to remember, your friendly guide will offer you a hint: "Alice Algae and Fred Fungus took a lichen to each other." And if you want to remember the five kinds of Alaskan salmon, consult the fingers of one hand: pink (pinkie); silver (ring finger); king (big, middle finger); sockeye (pointer or index finger); chum (thumb). Enviro humor is not sophisticated, but it is delivered with gentle self-irony.