A cewar ƙamus na Turanci na Oxford, "crustose thallus" yana nufin nau'in thallus, wanda shine jikin tsire-tsire na tsire-tsire marasa fure kamar lichen ko algae. Crustose thallus yana da kamannin ɓawon burodi kuma yana manne da saman da yake girma a kai. Yawanci lebur ne, tare da santsi ko granular surface kuma yana iya jeri cikin launi daga launin toka mai haske zuwa launin ruwan kasa mai duhu. Ana yawan samun lichens a kan duwatsu, bango, da bawon bishiya.