The New York Times – “Botanists have laid out evidence that dozens of North American trees, herbs, plants and shrubs have gone extinct since European settlers arrived. “It isn’t easy to say that anything has truly “gone extinct.” For starters, an untold number of creatures — especially teensy, nocturnal or otherwise cryptic ones — have vanished before humans ever noticed them. Once biologists suspect a documented species’ extinction, the challenge shifts to proving whether it has disappeared forever, or just disappeared from sight. Even when scientists are 99 percent certain something is gone, they may never know whether pathogens, habitat disturbance, invasive species, climate change or some other force drove them out of existence. “There’s a sense that we’ve got it down — that we know our flora and we know what’s extinct,” said Anne Frances, the lead botanist for NatureServe, which promotes wildlife conservation. That belief couldn’t be further from the truth, she said.

In a study published in August in Conservation Biology, Dr. Frances and 15 other researchers from across the United States quantified how many trees, shrubs, herbs and flowering plants have vanished from North America since European settlement. After compiling existing information on presumed extinct species and working with local botanists to vet the data, the group narrowed down a list of 65 plant species, subspecies and varieties that have been lost forever in the wild. That figure is almost certainly an underestimate, said Wes Knapp, a botanist at the North Carolina Natural Heritage Program and a co-author of the study. “That 65 is not rock solid,” he said. “We’re still documenting what’s on the ground, and you can never really prove a hypothesis like ‘extinct.’” After all, scientists rediscover extinct species all the time, as well as uncover secret extinctions hidden in natural history museum collections. “Humans like to put things into neat categories, but nature doesn’t present itself that way,” Dr. Frances said. “Every plant on this list is its own little mystery.”…”