''Stephanomeria malheurensis'', the Malheur wirelettuce, is a species of flowering plant in the family

Asteraceae Asteraceae () is a large family (biology), family of flowering plants that consists of over 32,000 known species in over 1,900 genera within the Order (biology), order Asterales. The number of species in Asteraceae is rivaled only by the Orchi ...

. It is

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

in the United States. It is a federally listed

endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, inv ...

. It was discovered in 1966 and the population at the type locality in Harney County is the only one ever known. For several years in the 1980s it disappeared. Scattered individuals have been noted over the years. Plants were grown from seed at the Berry Botanic Garden in

Portland Portland most commonly refers to: *Portland, Oregon, the most populous city in the U.S. state of Oregon *Portland, Maine, the most populous city in the U.S. state of Maine *Isle of Portland, a tied island in the English Channel Portland may also r ...

and planted at the original site. Some still survived as of 2001.''Stephanomeria malheurensis''.
Center for Plant Conservation. This species grows atop hills surrounded by flat land. The soils are derived from

tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock co ...

with a thin top layer of

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

. Associated plants in the habitat include Wyoming big sagebrush, yellow rabbitbrush,

basin wildrye ''Leymus cinereus'' is a species of wild rye known by the common names basin wild rye, Great Basin wild rye, and Great Basin lyme grass.

, and cheatgrass. ''

Stephanomeria exigua ''Stephanomeria exigua'', the small wirelettuce, is a perennial or biennial plant native to the western United States. It is thought to be the parent species of '' Stephanomeria malheurensis'' (Malheur wirelettuce), an endangered plant species f ...

'', the small wirelettuce, grows in the same area, and it is thought that the Malheur wirelettuce evolved from it. ''S. malheurensis'' is an annual and is susceptible to invasive species of plants, especially cheatgrass. It is thought to have evolved outside the usual model of

allopatric speciation Allopatric speciation () – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from ...

, from its parental species ''

''. As such this plant is one of the best plant examples of "quantum speciation," a concept closely aligned with

peripatric speciation Peripatric speciation is a mode of speciation in which a new species is formed from an isolated peripheral population. Since peripatric speciation resembles allopatric speciation, in that populations are isolated and prevented from Gene flow, ex ...

, parapatric speciation and

sympatric speciation Sympatric speciation is the evolution of a new species from a surviving Common descent, ancestral species while both continue to inhabit the same geographic region. In evolutionary biology and biogeography, ''sympatric'' and ''sympatry'' are ter ...

References

External links

* malheurensis Flora of Oregon Endangered plants Endemic flora of Oregon Endemic flora of the United States {{Cichorieae-stub