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Dudley Bluffs Twinpod
This member of the mustard family produces heart-shaped fruits.
About This Species
The Dudley Bluffs twinpod is one of 18 bladderpod species considered rare in Colorado. This species has distinctive heart-shaped seed pods that directly inspired the species name in its scientific name: “obcordata” is derived from the Latin ob- (meaning “reversely” or “inverted”) and cordatus (“heart-shaped”), referencing the distinctive upside-down heart shape of its fruit.
More Information:
Physical Characteristics
This perennial plant forms a rosette (a pattern in which horizontally growing leaves radiate outward, like the petals of a rose) that grows 4-8 inches high and 7 inches across. Bluish green leaves are oval or arrow-shaped and covered with satellite-shaped trichomes (hairs). Dudley Bluffs twinpods produce bright yellow, four-petaled flowers which, if pollinated, produce the characteristic heart-shaped fruits.
Range
Dudley Bluffs twinpods grow only in the Piceance Basin in Rio Blanco County. We know of only 12 locations where this plant grows, within a range of 274 square miles near the town of Meeker. They grow at elevations between 5,945 and 7,709 feet.
Habitat
These bladderpods only grow in white shale of the Green River formations, where they are found on outcrops or steep slopes exposed by creeks cutting down through the shale.
Many of the species these bladderpods grow with are also regional endemics to the shale slopes (found there and nowhere else on Earth), including dragon milkvetch (Astragalus lutosus) and Barneby's thistle (Cirsium barnebyi). More common co-occurring species include Indian ricegrass (Eriocoma hymenoides) and spearleaf buckwheat (Eriogonum lonchophyllum).
Threats to Species
Mining and oil and gas development are considered the main threats to this species, which are found only on oil-shale outcrops. In 2000, a nahcolite (a mineral used in soaps, detergents and glassmaking) plant was built within this species' range. Other threats include encroachment by invasive plants (primarily cheatgrass), livestock grazing, trampling by wild horses and possibly impact from off-highway vehicles. Road maintenance could also impact plants found along roadsides.