Placopsis lambii is distinguished by its placodioid thallus that features deeply notched and radiating edge lobes, a glossy upper surface, typically dark and somewhat rounded soralia, and non-lobate cephalodia that may be absent in certain samples. This species predominantly produces 5-O-methylhiascic and gyrophoric acids.[5]
Placopsis lambii has a widespread but scattered distribution. It has been recorded from many countries in Europe, Africa (Kenya, Lesotho, and Tanzania), South America (Bolivia, Chile), Central America (Costa Rica, Ecuador), New Zealand, and Asian Russia.[5]