O ne day last month on the Pacific island of Kauai, Steve Perlman was ready to throw himself off a cliff. In a blue t-shirt and cargo pants, Perlman, a botanist, was preparing to lower himself on a rope into Kalalau Valley Rim, a steep piece of land with neither hiking paths nor access roads. The rim sits inside Na Pali Coast State Park, where tourists come to see the rocky hillsides carved away by the Pacific. Where they don’t come is to the rocky hillsides inland that are covered by plants and, more frequently, hungry goats.

Perlman had fixed his eyes on one plant below, a small green specimen that seems to blend in with the flora around it. It’s