Mushrooms are collectibles and mushroom hunting is a venerable pastime. The fungi grow in woods on rotting logs, in the middle of a green lawn overnight and on clumps of decomposing cow dung in pastures. For thousands of years, people have been finding and consuming mushrooms for their taste, nutritional value and sometimes for their psychotropic effects. The mushrooms that grow on cow dung cover the spectrum from common edibles to exotic hallucinogens.
About 3,000 of the known 14,000 types of mushrooms are edible and one of the most common edible mushrooms is the simple 'button" mushroom, the Agaricus bisporus. Today those mushrooms are grown as a commercial cash crop in China and farmers use compost on bamboo shelves with steam humidity to force the fungi to grow. The compost can be made of easily obtained local materials and one simple mix is a base of paddy straw mixed with cow dung. In the U.S. button mushroom farmers use composts of decomposing plant matter with horse or poultry manure. White button mushrooms are sold fresh, canned, pickled and marinated and in soups and sauces.
Mushrooms are fungi and some of them are highly poisonous, so it is safest to consume market mushrooms from a reputable source. The Cyathus striatus is one you should photograph and leave in the field. The mushrooms are brownish to reddish-brown on the exterior and black inside, under the cap. Younger Cyathus striatus are slightly shaggy or hairy looking but the cone-shaped caps smooth out with maturity. They grow very densely in North America on organic debris, all kinds of dung including cow patties, on wood chips, sawdust and even on soil that has been fertilised with manure. Their season is July through October and they should not be eaten so, if you stumble across them on a mushroom hunt, keep searching.
The most famous cow dung fungi are members of the Psilocybe cubensis family -- so-called psychedelic mushrooms or 'shrooms. They spring up all over the world where cattle have been grazing and prefer to grow directly on cow patties, most often those that are decomposing in the field. The 'shrooms grow in warm climates and appear from February to November. They have large yellow-brown caps that lighten as they mature and when bruised they turn blue. Their spores are spread by cattle egrets, Crested Caracara birds, the wind and by the feet of humans and cattle moving around the field. Traditionally, native tribes used, and still use, hallucinogenic mushrooms in rituals and P. cubensis is the most widely cultivated and consumed of the psychedelics. The mushrooms were extremely popular in the sixties and people still hunt for them at night in cattle pastures. It is illegal to possess P. cubensis in the United States.