Mushrooms, it turns out , are just the visible part of an awesome organism known as mycelium, most of which lies below ground. Neither animal nor vegetable, this vast network of cells has been sharing nutrients and forming connections for billions of years, breaking down decaying matter and transforming it into living soil.

Making visible this endless cycle of decomposition and regeneration — and much more besides — Louie Schwartzber g’s lightly informative, delightfully kooky documentary, “Fantastic Fungi,” offers nothing less than a model for planetary survival. Our primary guide to ’shroom splendiferousness is the mycologist Paul Stamets (at one point sporting a Grateful Dead hat), who, vividly assisted by time-lapse cinematography, leads us through fungus-related science, history and even a dash of politics. (As some of you might remember, President Nixon wasn’t a fan of the psychedelic properties of some mushrooms.)