Few people pop to the supermarket and discover a new species.

But DNA testing has revealed that three unamed species of mushroom that are new to science have been found in a bag of dried porcini that came off a shop shelf in London.

While porcini mushrooms are served in many restaurants, relatively little is known about them scientifically.

To explore the nature of the popular cooking ingredient, mycologists Bryn Dentinger and Laura Martines-Suz of the Royal Botanic Gardens at Ken, in south west London, sequenced the DNA of bg of dried Chinese porcini.

There were 15 pieces of mushroom in the bag and all of them belonged to three unnamed species, indicating that experts know relatively little about the vast group of fungi.