The pawpaw may be waiting for an animal that no longer exists. ⁠ ⁠ Thousands of years ago, North America was home to mastodons, giant ground sloths and other megafauna capable of eating large fruits — and carrying their seeds across the landscape. Then those animals disappeared.⁠ ⁠ But some of the fruits remained.⁠ ⁠ The pawpaw, Asimina triloba, is one of them. Its large fruits and seeds have long intrigued scientists studying the ecological relationships left behind by extinct animals. Today, its fruit still feeds turtles, deer, raccoons, bears and other wildlife, while its leaves are essential food for zebra swallowtail caterpillars.⁠ ⁠ And another remarkably effective seed disperser has entered the story — us.⁠ ⁠ In The American Gardener, Nancy Lawson explores what happens when plants outlive some of the animals they evolved alongside — and the role humans can play in creating new ecological relationships.⁠ ⁠ As Lawson writes, “We carry the torch of seed-dispersing animals who’ve di...