American plants that have gone extinct
The world is facing an extinction crisis. We are currently in the midst of what scientists call the Anthropocene extinction, a mass extinction event driven by human actions such as predation and urbanization. Of the 8 million total animal and plant species on Earth, about 1 million are threatened with extinction, according to a 2019 global assessment by the U.N. Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES). This one in eight rate is far higher than the average extinction rates of the past 10 million years—and in many places, conditions are only getting more dire.
While we often think of extinction in terms of faraway places like Antarctica or the Amazon rainforest, this cruel process is actually taking place in our own backyards. David Wilcove, a conservation scientist from Princeton University, estimated that there are 14,000 to 35,000 endangered species in the U.S.—that's up to 18% of our country's plants and animals. And while it's easy to study the population decline of large animals like the American bison or the California condor, smaller animals and plants are harder to track, leaving many scientists to suspect that sweeping estimates like Wilcove's are far under the mark.
In a paper published in Nature in 2019, a team of biologists led by Aelys Humphreys of Stockholm University set out to determine the current state of plant extinction by compiling species lists from around the world. They found that, between 1900 and 2018, seed plants were lost at a rate of about 25.6 extinctions per million species-years; in other words, an average of 2.3 species have gone extinct each year for the past 250 years. Still, even these estimates are likely low due to a lack of information: It takes time to find a new plant and even more time to definitively characterize it as a new plant. Sometimes, a new plant is found only once, described, and then never seen again, to the great dismay of botanists around the world.
Stacker used the database of extinct plants compiled by Humphreys and her team to develop a list of 21 plants that were lost to science here in America. Many of these plants were collected and classified by botanists exploring the western and southern parts of America in the late 1800s and early 1900s, then driven to extinction by urbanization and other environmental changes later in the 20th century. The list is organized here by plant group (annual herb, herbaceous perennial, or woody perennial), then by family.
Read on to discover these lost American gems, from a flowering tree described by the founder of the New York Botanical Garden to a tiny parasitic flower that botanists still search for today.
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Shinyfruit popcornflower
- Scientific name: Plagiobothrys lamprocarpus
- Family: Boraginaceae
- Group: Annual herb
- Climate: Temperate
- Former home range: Oregon
This small herb was discovered in 1921 by Charles Piper, a botanist and longtime worker for the U.S. Department of Agriculture, in Grants Pass, Ore. The species hasn’t been sighted again since Piper’s initial collection and is now presumed extinct; agricultural and urban developments are the suspected causes of this loss.
Mayacamas popcornflower
- Scientific name: Plagiobothrys lithocaryus
- Family: Boraginaceae
- Group: Annual herb
- Climate: Temperate
- Former home range: California
In 1884, the Mayacamas popcornflower was spotted in northern California by Mary Katharine Brandegee, a pioneering female scientist who was the third woman to ever matriculate at the medical school of the University of California. The flower hasn’t been seen since 1903—like its relative, the shinyfruit popcornflower, it may have fallen prey to urban development on the West Coast.
Lemmon's jewelflower
- Scientific name: Streptanthus lemmonii
- Family: Brassicaceae
- Group: Annual herb
- Climate: Subtropical
- Former home range: Arizona
Lemmon’s jewelflower was an oddly shaped flower in the mustard family (Brassicaceae), distinguished by large, oblong leaves and a number of thin tulip-like buds. While this species hasn’t been seen in the wild since the 1940s, its close relative, Caulanthus lemmonii (also colloquially called Lemmon’s jewelflower), lives on in southern California.
Merced monardella
- Scientific name: Monardella leucocephala
- Family: Lamiaceae
- Group: Annual herb
- Climate: Subtropical
- Former home range: California
Merced monardella, like other plants in the mint family (Lamiaceae), had highly aromatic leaves and flowers. This species was last spotted in California’s grasslands in 1941; botanists believe it was pushed out by agricultural expansion in the state. Recent searches for it in 1990 and 1997 have been fruitless.
Pringle monardella
- Scientific name: Monardella pringlei
- Family: Lamiaceae
- Group: Annual herb
- Climate: Subtropical
- Former home range: California
Pringle monardella was first identified in 1882. Like its relative, the Merced monardella, this plant was last seen in 1941; its habitat in California's scrublands was lost to urbanization.
Caddo false foxglove
- Scientific name: Agalinis caddoensis
- Family: Scrophulariaceae
- Group: Annual herb
- Climate: Subtropical
- Former home range: Louisiana
In 1913, the botanist Francis Pennell discovered a population of Caddo false foxglove flowers in Caddo Parish, near the city of Shreveport in Louisiana. Other scientists have searched for the species in the 1970s, '80s, and '90s to no avail, but the type of dry, loamy oak forest that Pennell described in his collection notes still survives elsewhere in the state, so botanists are optimistic that this small, purple flower may be rediscovered.
Nuttall's false foxglove
- Scientific name: Agalinis nuttallii
- Family: Scrophulariaceae
- Group: Annual herb
- Climate: Temperate
- Former home range: Oklahoma, Arkansas
This flower species, similar to its relative, the Caddo false foxglove, is known from a singular population: botanist and zoologist Thomas Nuttall found it in 1819 near the Arkansas River, near the border of present-day Arkansas and Oklahoma. Nuttall’s false foxglove was tragically left off of modern plant lists and records, and was overlooked as a potential conservation priority until 1995.
Banded Trinity
- Scientific name: Thismia americana
- Family: Burmanniaceae
- Group: Herbaceous perennial
- Climate: Temperate
- Former home range: Illinois
University of Chicago graduate student Norma Pfeiffer discovered the banded Trinity in 1914 while exploring the wetlands around Lake Calumet. She became fascinated by the tiny white plant and made it the subject of her doctoral thesis; as she discovered, banded Trinity mostly lived underground, taking nutrients from fungi in the soil, and only popped aboveground in the summer to flower and reproduce. The flower caught the attention of botanists around the world, but before any other scientists could research its fascinating properties, it disappeared in 1916 when a barn was built near its habitat—and has been missing ever since. Still, naturalists go searching for the parasitic plant every year in what has been dubbed the Thismia Hunt.
Livermore sandwort
- Scientific name: Arenaria livermorensis
- Family: Caryophyllaceae
- Group: Herbaceous perennial
- Climate: Temperate
- Former home range: Texas
Livermore sandwort, a matted, moss-like plant, was only found in the Davis Mountains in western Texas, where it grew in the crevices of cliffs and bare walls around 7,000 feet above sea level. The species is thought to be related to A. lycopodioides, a similar mossy plant that lives in the mountains of central Mexico.
Shasta River mariposa lily
- Scientific name: Calochortus monanthus
- Family: Liliaceae
- Group: Herbaceous perennial
- Climate: Subtropical
- Former home range: California
American botanist Edward Lee Greene named or redescribed over 4,000 species on the West Coast over his lifetime, from 1843 to 1915. One of these species was the Shasta River mariposa lily, a small flower with three pink petals, which he found on the banks of the Shasta River in Siskiyou County, California. The flower has not been seen since.
Jeff Davis Parish Indian paintbrush
- Scientific name: Castilleja ludoviciana
- Family: Scrophulariaceae
- Group: Herbaceous perennial
- Climate: Temperate
- Former home range: Louisiana
The Jeff Davis Parish Indian paintbrush, like the Caddo false foxglove, was discovered by Francis Pennell in Louisiana in 1915. Although this Louisiana flower has not been seen again since Pennell’s collection, about 200 other species of paintbrush (Castilleja) persist on the West Coast and in Asia, including the Scarlet paintbrush (Castilleja coccinea), which is thought by some botanists to be a synonym of Jeff Davis Parish Indian paintbrush. Paintbrush flowers are recognizable by their spiky red petals, which are edible and are used by some Native American tribes for medicine.
Montezuma County beardtongue
- Scientific name: Penstemon parviflorus
- Family: Scrophulariaceae
- Group: Herbaceous perennial
- Climate: Subtropical
- Former home range: Colorado, New Mexico
Francis Pennell was well known for his studies of the figwort family (Scrophulariaceae): He also discovered Montezuma County beardtongue, collecting it in the Pinyon-juniper woodland in Montezuma County, Colorado, in 1890. Many relatives of the species persist; beardtongue (Penstemon) is the third-largest genus of flowering plants on the West Coast, including over 250 species of brightly colored (mostly bright blue) tubular flowers.
Chenopod brickellbush
- Scientific name: Brickellia chenopodina
- Family: Asteraceae
- Group: Woody perennial
- Climate: Subtropical
- Former home range: New Mexico
The Chenopod brickellbush, like several other species on this list, is in the daisy family (Asteraceae), a large and diverse group of flowering plants. It was discovered in 1903 by Benjamin Lincoln Robinson, a well-respected American botanist who served as the curator of Harvard University’s herbarium. Modern analysis suggests that this flower was likely a modified version of Chihuahuan brickellbush (Brickellia floribunda), which grew on a polluted bank of the Gila River after a flood.
Palo Alto thistle
- Scientific name: Cirsium praeteriens
- Family: Asteraceae
- Group: Woody perennial
- Climate: Temperate
- Former home range: California
In 1897, the Palo Alto thistle was discovered by James Francis Macbride, an American botanist best known for studying the plants of Peru. The thistle hasn’t been spotted since 1901; some experts hypothesize that it was introduced from Europe and did not take to the American West. Like other thistle species, it grew up to 3 feet tall and had symmetrical, white disc flowers that were visited by many different insect pollinators.
New Mexico sunflower
- Scientific name: Helianthus praetermissus
- Family: Asteraceae
- Group: Woody perennial
- Climate: Subtropical
- Former home range: New Mexico
New Mexico sunflower, or "lost sunflower," also a member of the Asteraceae family, was collected by botanist Elba Emanuel Watson in 1851 and has not been seen since. Modern botanists have had trouble pinpointing where, exactly, this flower's type specimen was collected: Watson's notes describe the location as "the head of the Rio Laguna," which is now the Rio San Jose in New Mexico, but his expedition was in Arizona on the collection date. Although developments and invasive species have harmed potential sunflower habitats in the past century, the closely related paradox sunflower (Helianthus paradoxus) has been found in New Mexico, so botanists are optimistic that the New Mexico sunflower could be found again.
Grand Junction catseye
- Scientific name: Cryptantha aperta
- Family: Boraginaceae
- Group: Woody perennial
- Climate: Temperate
- Former home range: Colorado
Alice Eastwood was a Canadian American botanist who built the botanical collection at the California Academy of Sciences, published over 300 scientific papers, and authored 395 plant species names. In 1892, she found the Grand Junction catseye, a perennial herb with small, white flowers, near Grand Junction in western Colorado. The area has since seen a lot of agricultural and urban development, but since Eastwood’s description of where she found the flower was vague, modern botanists believe the flower may persist in a still-unsearched area.
San Luis watercress
- Scientific name: Rorippa coloradensis
- Family: Brassicaceae
- Group: Woody perennial
- Climate: Temperate
- Former home range: Colorado
San Luis watercress, also called Colorado watercress, was found in 1875 along the banks of the San Luis Lakes. The species was distinctive for its extremely large buds and flowers with spatula-shaped petals. About 80 other watercress species persist around the world in Europe, central Asia, and Africa.
Largestipule leather-root
- Scientific name: Orbexilum stipulatum
- Family: Fabaceae
- Group: Woody perennial
- Climate: Temperate
- Former home range: Kentucky
The only known specimens of largestipule leather-root, also known as Falls-of-the-Ohio scurfpea, were collected on Rock Island, a small island in the shallow rapids of Kentucky’s part of the Ohio River. Dr. Charles Wilkins Short collected many specimens of the plant in the 1850s and 1860s, but it was believed extinct after 1881. While another Rock Island species, Short’s goldenrod (Solidago shortii), was rediscovered in 1939, it seems unlikely that we will ever see largestipule leather-root again, as in his decades of study, Dr. Short never saw it in fruit.
Onehair mountainmint
- Scientific name: Pycnanthemum monotrichum
- Family: Lamiaceae
- Group: Woody perennial
- Climate: Temperate
- Former home range: Virginia
Onehair mountainmint was discovered in 1936 by Merritt Lyndon Fernald, an American botanist who coauthored the book "Edible Wild Plants of Eastern North America." As a member of the mint family (Lamiaceae), onehair mountainmint was one such edible plant, used in cooking and making herbal tea.
Luna County globemallow
- Scientific name: Sphaeralcea procera
- Family: Malvaceae
- Group: Woody perennial
- Climate: Subtropical
- Former home range: New Mexico
Cedric Porter discovered Luna County globemallow, also known as Porter's globemallow, in a sandy arroyo in the Chihuahuan desert grassland. The plant was a stout, perennial herb that grew up to 9 feet tall with multiple branches and purple-pink flowers. Some botanists believe Porter's specimens were actually a variant of hot springs globemallow (Sphaeralcea polychroma), a closely related species.
Rock Key devil's-claws
- Scientific name: Pisonia floridana
- Family: Nyctaginaceae
- Group: Woody perennial
- Climate: Wet tropical
- Former home range: Florida
Rock Key devil’s-claws, a species of flowering tree, was first identified by Nathaniel Lord Britton, a botanist and taxonomist famous for co-founding the New York Botanical Garden with his wife, fellow botanist Elizabeth Gertrude Knight. This tree was also known as the Rock Key Catchbirdtree and is similar to other trees in the Pisonia group which persist on islands in the Caribbean and Indo-Pacific. All Pisonia trees have sticky seeds, which are intended to stick to seabirds and disperse with those birds to other islands, but often instead trap those birds in deadly cocoons, preventing them from moving or flying.
