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How Many Plants Have We Wiped Out? Here Are 5 Extinction Stories

作者:admin 2020-10-17

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ImageHow Many Plants Have We Wiped Out? Here Are 5 Extinction Stories

Despite the fact that it’s extinct, you could reasonably venture upon Franklinia alatamaha.

Considered “extinct in the wild,” the Franklinia tree — along with six other plants listed in the recent study — now exists only in cultivated spaces such as arboretums or botanical gardens.

John Bartram, King George III’s botanist in the Americas, and his son William first described the species (and named it for family friend Benjamin Franklin) after stumbling upon the unfamiliar tree along Georgia’s Altamaha River in 1765.

In a lucky twist, the younger Mr. Bartram returned a few years later to collect seeds and cuttings, and brought them to Philadelphia where the first cultivated Franklinia tree bloomed in 1781. Within a quarter-century, in 1803, the species was spotted in the wild for the last time.

Today, any Franklinia trees you might encounter in cemeteries, gardens and parks are descendants of Mr. Bartram’s cultivations. “It wasn’t meant to prevent extinction,” Mr. Knapp said, “but it did.”

It’s unclear how the tree disappeared, though some have suggested a soil-borne cotton pathogen, over-collection by nurseries or a change in regional fire frequency could have played a role in its demise.

“What we have is conjecture. We really have no idea why it’s gone,” Mr. Knapp said. “But you can buy it if you go to the right place.”

Credit...SBS Eclectic Images/Alamy

How do you lose a 3-foot-tall daisy forever? By mistaking it for a different flower.

At least, that’s what happened to Marshallia grandiflora, a large flowering plant last collected in 1919.

Native to two western counties in North Carolina, the species was, until this year, incorrectly lumped in with a different, more wide-ranging daisy.

In comparing current Marshallias with older herbarium specimens, a trio of botanists noticed a remarkable size and shape difference.

By the time it was first described in June, the “new” species was long extinct, for reasons that are not known. Three other extinct plants listed in the new paper were also similarly discovered in natural history collections within the last 25 years.

“We’re still doing the basic science to untangle what the species are,” said Alan Weakley, director of the University of North Carolina, Chapel Hill’s Herbarium, and a co-author of the study. “There are undoubtedly more undescribed extinct species sitting in herbaria, collected 100 years ago.”

Credit...Steffen Hauser/botanikfoto, via Alamy

Native Americans historically ate the young stems of Solomon’s seals, a wildflower belonging to the same family as asparagus, or cooked their starchy roots into breads and soups. Today, the species continues to be used in herbal medicine.

While most of small Solomon’s seal is doing just fine in the wild, one of its varieties, Polygonatum biflorum var. melleum, is presumed extinct.

Scientists are split on whether the melleum variety, last collected in 1930 and believed to be native to Michigan and Ontario, is distinct enough to be categorized apart from other Solomon’s seals.

“It’s really murky. The data argues it may or may not even be real,” Mr. Knapp said. “This is on the fringe.”

While the melleum variety made the cut for August’s paper, uncertainty over the existence or status of hundreds of plants left them off the list in their study.

Credit...University of Chicago Press, via JSTOR

In 1912, Norma Etta Pfeiffer, a 24-year-old graduate student at the University of Chicago, made a marvelous botanical discovery near Chicago’s Lake Calumet: a truly teensy plant adorned with bead-sized flowers.

The plant, which she named Thismia Americana, belongs to a rare genus that lives as a parasite on subterranean fungi, stealing their energy instead of converting sunlight through photosynthesis.

“They’re small and cryptic and mostly underground. We don’t even know much about the ones we’ve described,” said Paul Marcum, a botanist at the Illinois Natural History Survey.

Like almost two out of three of the plants listed in August’s study, Thismia Americana is only ever known to have existed in one location, making it extremely vulnerable to any changes in land use.

Shortly after Dr. Pfeiffer found the centimeter-tall plant, industrial development destroyed the discovery site.

That hasn’t kept subsequent generations of Chicagoans from hunting for it — although Field guides for Thismia seekers offer little help: “Where to look: Honestly? Your guess is as good as ours.” The species has not been spotted since 1916.

“It’s the holy grail,” Mr. Marcum said. “I still believe it could be out there. I think somebody will be on their hands and knees searching in the soil, and get lucky.”

Credit...Natural History Collection/Alamy

The Franciscan Manzanita has endured not one, but several brushes with extinction.

The shrub species, Arctostaphylos franciscana, was presumed to be extinct in the wild for nearly 70 years, stamped out by construction in San Francisco’s Presidio park.

Then, in 2009, Daniel Gluesenkamp, now the executive director of the California Native Plant Society, stumbled upon Franciscan Manzanita in overgrown vegetation near Golden Gate Bridge Park.

Unfortunately, the site of its rediscovery lay directly in the path of a “shovel ready” project. “The next best thing we could do was dig this thing up and move it,” Mr. Knapp said.

Conservationists relocated the shrub to a protected site and it began propagating. Like the Franklinia tree, the Franciscan Manzanita is now considered extinct in the wild.

“Part of me is sad that we couldn’t allow it to exist in its last remaining natural spot,” Mr. Knapp said. “It’s not a great solution, but it’s much better than being extinct.”

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