What's life to a lichen?

It is easy to overlook this thought that life just is. As humans we are inclined to feel that life must have a point. We have plans and aspirations and desires. We want to take constant advantage of all the intoxicating existence we've been endowed with. But what's life to a lichen? Yet its impulse to exist, to be, is every bit as strong as ours-arguably even stronger. If I were told that I had to spend decades being a furry growth on a rock in the woods, I believe I would lose the will to go on. Lichens don't. Like virtually all living things, they will suffer any hardship, endure any insult, for a moment's additional existence. Life, in short, just wants to be. But-and here's an interesting point-for the most part it doesn't want to be much.

--Bill Bryson, A Short History of Nearly Everything

Suttree in the woods was surprised to find small flowers still. He fell into silent studies over the delicate loomwork in the moss. Annular forms of lichens fiery green that sprawled across the stones like tiny jade volcanoes. The scalloped fungus that ledged old rotted logs, flangeous mammary growths with a visceral consistency and pale indianpipes in pulpy clusters among the debris of humus and rich decay and mushrooms with serrate and membraneous soffits where under toads are reckoned to siesta. Or elves, he said. In breeks of kingscord, shirts paned up of silk tailings, no color like the rest. A curious light lay in the forest. He was squatting in the rich and murky earth, the blanket about his shoulders. He wondered could you eat the mushrooms, would you die, do you care. He broke one in his hands, frangible, mauvebrown and kidneycolored. He'd forgotten he was hungry.

--Cormac McCarthy, Suttree