Fungi on London Underground

Occasionally I wonder if I am the only one who is so crazy about mushrooms. Then I come across an article like this one, and it becomes very clear that I am not alone in the universe.

In short, it tells about a few mycologists who went on fungal foray in London underground, in order to find out which of the lines is the mouldiest. The winner by a small margin was, unexpectedly, the newest, Jubilee line, where unfortunate commuters breathe in 1 fungal spore a minute, and unlike other lines these spores are not from penicillin, and why that has to be so, remains an unsolved mystery.

So, what made those people to look for fungi in the underground? Perhaps, Nils Norman's vision of Piccadilly line in 2050? After all, in its bottom left corner it prominently features Hammersmith Mushroom Facility. Not too far from Green Park, where it intersects with Jubilee line. Hmmm, I wonder what those unknown spores actually are...