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Rarest North American Plants & Flowers

Helianthus tuberosus image by kelly marken from

Over 1,900 plant and animal species have been added to the endangered or threatened list under the Endangered Species Act since its inception in 1973. Of these, the U.S. Fish and Wildlife Service lists 719 species of flowering plants, some of which grow in only a handful of sites in very restricted ranges. A large majority of these endangered species occur at least in part on privately managed lands, where public and private stakeholders work to bring as many species as possible back to self-sustaining levels.

Mead's Milkweed (Asclepias meadii)

A native of the American prairies, the range of this cream-flowered milkweed once stretched from Wisconsin to Missouri, but the plant now occurs only in scattered areas in Illinois, Iowa, Kansas and Missouri. Mead’s milkweed was also recently re-introduced in Indiana.

Four-Petal Pawpaw (Asimina tetramera)

This shrubby relative of the tropical papaya is found in only two counties on the eastern coast of Florida. Only several dozen individuals remain, and these reproduce slowly, though the plant regenerates swiftly and multiplies after being razed by fire. Like its pawpaw cousin to the north, the fruits are edible and relished by raccoons, tortoises and mice.

Bush's Poppy-Mallow (Callirhoe bushii)

Vibrant magenta in color and shaped like wine cups, the flowers of this American prairie native are what make the plant memorable. Roughly 50 sites in Kansas, Missouri, Oklahoma and Arkansas comprise the plant’s present-day range.

Miner's Candle (Cryptantha subcapitata)

Throughout most of the year, the silvery-green foliage of this stubby, high desert plant resembles most of its neighbors in the Wind River basin of Fremont County in Wyoming. But the miner’s candle, named for its brilliant, white, five-petaled flowers, consists of only three populations in a 1,400-acre area.

Okeechobee Gourd (Cucurbita okeechobeensis)

Once common along the shores of Florida’s St. John’s River and Lake Okeechobee, this eponymous gourd must rely on nearby trees to climb in order to successfully flower and fruit. But as the area changed for development and agriculture, the Okeechobee gourd dwindled. It remains of high interest to science, however, for its natural resistance to many common vegetable pathogens, including powdery mildew and cucumber mosaic virus.

Tennessee Coneflower (Echinacea tennesseensis)

This extremely rare wildflower was the second species listed after the Endangered Species Act went into effect in 1973. Thought to be extinct until re-discovered in middle Tennessee in the 1970s, several sites were destroyed soon after by development and construction. The plant is restricted to only five populations in a 14-mile radius.

Appalachian Avens (Geum radiatum)

Growing on rocky clifftops in the Appalachian mountains of North Carolina, Tennessee and Virginia, this native wildflower produces bright yellow, buttercup-like flowers during its autumn blooming period. Geum radiatum now grows in only 11 sites, and several of these sites have less than a dozen individual plants.

Desert Sunflower (Helianthus niveus ssp. tephrodes)

The desert sunflower, as the name implies, grows in the sand-dune deserts of Baja California, southern Arizona and scattered sites up through northern California. The plant is only known to grow in four sites within this region. Illegal recreational vehicle use continues to threaten the future of this plant.

Biddle’s Lupine (Lupinus biddlei)

Like other lupines, Biddle’s lupine features a showy spike of flowers above dark green, palm-shaped leaves. This species is found on rocky slopes and poor soils in two geographically distinct areas in western Oregon.

Plymouth Rose Gentian (Sabatia kennedyana)

The candy-pink flowers of this endangered wildflower resemble daisies, and colonies once grew along the Atlantic coastline from Nova Scotia to South Carolina. The rose gentian now occurs only in scattered sites throughout its former range, and population numbers vary widely depending on annual rainfall amounts.

Madrean Ladies' Tresses (Spiranthes delitescens)

This Arizona species of terrestrial orchid grows at elevations of around 5,000 feet, preferring marshy growing conditions. Four known sites exist, three of which are on private grazing lands, and other populations may also be present in Mexico. Individual plants rarely live longer than four years.

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