It’s decorative gourd season, if you know what I mean. But to what do we owe this festive time? According to a new study published in Molecular Biology and Evolution, it was a doubling of chromosomes 90 million to 102 million years ago that transformed melonlike plants known as curcurbits into today’s cucumbers, watermelon, squash, pumpkin, zucchini, and of course, gourds. The process, “cucurbit-common tetraploidization,” occurred in a single common ancestor of the family, according to The New York Times. Over time, additional mutations gave rise to the sweet, sweet cornucopia of ultrafestive gourds that we all love to decorate our houses with when the air gets chilly. Thanks tetraploidization!