Yeah, lichens are the stubborn survivors of the wasteland, hanging on where most life gives up. In a terrarium they’re almost like a low‑maintenance vitamin C pack. On the surface, you could harvest the greenish biomass for a quick boost of nutrition—just a few grams mixed into your rations will give you a dose of antioxidants and a splash of moisture. Medicinally, lichens have a long history of treating sores and infections; crush a few into a paste and apply it to a cut, or steep them in a weak brew to create a natural antiseptic. If you’re out on the road, you can use them as a makeshift filter. Layer crushed lichen between sand and charcoal in a container, and it’ll help remove particulates and some radiation from water. And if you’re desperate, the lichens can even be ground up as a filler in improvised medicine bags—adds bulk and a bit of hope that the thing’s actually doing something. Just remember, no lichen can replace a proper ration, but in a world where nothing grows, it’s a handy trick.