The surprising evolutionary history of pumpkins and squashes

IN PARTS of the world where autumn is underway, squashes are now on the menu, and shops are stocking up on pumpkins for Halloween. I haven’t always been a fan of squashes, but the more I have learned about their evolutionary history, the more I have been charmed by how such unlikely and unpromising fruits came to spread worldwide.

There is a beguiling diversity of squashes and pumpkins, and their range of shapes, sizes and colours gives them much aesthetic appeal. But they all belong to one genus – Cucurbita – and fall broadly into only six main species or subspecies.…