Fungi - Edible Mushrooms

Mushrooms are the umbrella-shaped fruiting body (sporophore) of certain fungi. Popularly, the term mushroom is used to refer to edible sporophores, whereas toadstool is used to denote inedible varities, although in reality, there is no scientific distinction between the terms. I will be saying 'mushroom' here as I will be referring to edible varieties, and I had never heard the word sporophore before now. 

There are a few ways to define the edibility of mushrooms - some are totally harmless whether eaten raw or cooked, others may cause certain people to have severe allergic reactions, and a few are poisonous when raw but perfectly safe when properly cooked and prepared. In addition, there are species of mushroom that, while technically edible, are too tough, smelly or gelatinous to want to eat. I have seen these types of mushrooms cleverly described as "edible, but not incredible", a turn of phrase which I think is kind of genius. So after we discount the definitely should not eat types, and the would rather not eat types, we can say that, of the approximately 50,000 species of sporophores worldwide, around 5% can be considered 'edible mushrooms'.

The human consumption of mushrooms likely began during the hunter-gatherer period. However, it was not until the 17th century that people were able to effectively cultivate them, and so they had to be collected from the wild. Throughout history, various civilisations have considered mushrooms as special, and in some cases supernatural. For example, the Eygyptians believed mushrooms to be plants of immortality, leading the Pharos to declare that only they could eat them, and the Romans thought mushrooms were the food of the gods. But maybe this degree of esteem wasn't totally unwarranted, after all, mushrooms have been used for medicinal purposes for thousands of years and, more recently, Japanese research claims that the Shiitake mushroom may contain chemicals which can help to boost the immune system.

Today, mushrooms are widely consumed. One of the most popular types is the Agaricus bisporus, which is cultivated in over seventy countries globally. When immature and white, this mushroom is known by names including the white mushroom or button mushroom, and when immature and brown, one of its common names it the chestnut mushroom. Alternatively, if it is sold when mature (with a cap measuring 10-15cm), the same mushroom may be known as the portobello mushroom.

However, some mushroom varieties remain difficult to cultivate and harvest, so remain delicacies, accessible to only a few people. The most expensive species is the yartsa gumbu, a parasitic fungus which infects the bodies of ghost moth caterpillars, and then slowly eats its host alive. In spring, the fungus emerges through the caterpillars head. The resulting mushroom is long and thin and relatively easy to harvest, but can only be found in the  Himalayas and the Tibetan Plateau, at altitudes of around 3,000 - 5,000 metres. The best quality yartsa sells for about £1,500 an ounce. It is also considered as an aphrodisiac, but those sorts of side effects are for a different 500 words assignment.