Do truffles grow from the air?

Question

I found an ancient text which states that truffles do not "grow (derive their growth?) from the ground". I have found two medieval opinions on what that means:

1. They "don't have roots in the ground, and their growth is from the air."
2. Their roots don't have (twigs? ‎‎‎shoots? ‎‎‎tendrils? ‎‎‎thin branches?) which (lit. "do the action of (previous word)/ become (previous word)". Branch out?) under the ground, and (from them? With them?) (fertilize? Become fertilized? Pollinate? Become pollinated? Be fruitful?).

Are those descriptions accurate in light of modern understanding? Is there any sense in which "their growth is from the air" true? How exactly do they grow, and where does their sustenance come from? I have looked at a number of articles, but have had trouble understanding them.

P.S: Please forgive the many possible translations. The true translation may only be a similar word to the ones provided, but not actually any of them. Going through ancient texts can be difficult sometimes. I would also prefer to leave the text unnamed.

Answer 1

A truffle is the fruiting body of a fungus.

The truffle fungus spends most of its time as an interconnected network of fine strands called mycelia. The mycelia function like plant roots: they absorb water and nutrients from the soil around them. They connect to the roots of actual plants, where they provide the plants with water and nutrients in exchange sugar (which the plant produces by photosynthesis).

The mycelia strands are so fine, they are essentially invisible to the naked eye. Even if the people of the time when this author lived could see the mycelia, there's no obvious connection between the mycelia and the fruiting bodies. In the sense that mycelia are analogous to roots, it's not true that they "don't have roots in the ground." But it was reasonable for the author to think that.

One individual fungus can mate with another fungus by intertwining their mycelia. After they have exchanged genetic material, each fungus can produce a fruiting body. Remember that the fruiting body is the actual truffle that we eat. The fruiting body produces spores. Spores are like seeds; each spore can grow into a new individual fungus.

Many types of fungus spread their spores through the air. For that type of fungus, it is true that "their growth is from the air." However, truffles grow underground, and their spores are not spread through the air. They are spread by the animals that eat the truffle. So the truffle growth is not from the air, in any sense. It would be more accurate to say that "their growth is from the pig." Less Romantic, though.

Summary:

These statements from your ancient text are untrue. However, they are perfectly reasonable misconceptions based on the evidence that was available in ancient times. I have no doubt you would find similar explanations of truffles and mushrooms in other ancient texts. Without the benefit of modern science, mushrooms seem to magically appear from nowhere, then melt away just as quickly and mysteriously. See also: the fairy ring of Western Europe folklore.