Question: Which is native to farther west, Vancouveria or Sauromatum?

Context paragraphs:
Eureka, Nunavut: Eureka is a small research base on Fosheim Peninsula, Ellesmere Island, Qikiqtaaluk Region, in the Canadian territory of Nunavut.  It is located on the north side of Slidre Fiord, which enters Eureka Sound farther west.  It is the third-northernmost permanent research community in the world.  The only two farther north are Alert, which is also on Ellesmere Island, and Nord, in Greenland.  Eureka has the lowest average annual temperature and the lowest amount of precipitation of any weather station in Canada.

Fort Gibson: Fort Gibson is a historic military site located next to the present day city of Fort Gibson, in Muskogee County Oklahoma.  It guarded the American frontier in Indian Territory from 1824 until 1888.  When constructed, the fort lay farther west than any other military post in the United States; it formed part of the north–south chain of forts intended to maintain peace on the frontier of the American West and to protect the southwestern border of the Louisiana Purchase.  The fort succeeded in its peacekeeping mission for more than 50 years, as no massacres or battles occurred there.  The fort site is now managed by the Oklahoma Historical Society as the Fort Gibson Historical Site.  It is a National Historic Landmark.

Arizona State Route 389: State Route 389, also known as SR 389, is a state highway in far northern Arizona serving the Arizona Strip.  SR 389 stretches from the Utah border at Colorado City, southeast to Pipe Spring National Monument, and ends at U.S. Route 89A in Fredonia; it is the only major east–west route between these two towns, and also serves to connect Fredonia with points farther west such as St. George, Utah.

Monashee Mountains: The Monashee Mountains are a mountain range lying mostly in British Columbia, Canada, extending into the U.S. state of Washington.  They stretch 530 km from north to south and 150 km from east to west.  They are a sub-range of the Columbia Mountains.  They are limited on the eastern side by the Columbia River and Arrow Lakes, beyond which lie the Selkirk Mountains, and by the upper North Thompson River and the Interior Plateau on the west.  The northern end of the range is at the southern end of the Robson Valley just south of the town of Valemount.  The southern extremity of the range is in Washington State, where the Kettle River Range reaches just down to the confluence of the Kettle River and the Columbia, and also farther west to the southern extremity of the Okanagan Highland (spelled Okanogan Highland in the US) just northeast of the confluence of the Okanogan and Columbia rivers at Brewster and Bridgeport.

Arnoglossum reniforme: Arnoglossum reniforme (great Indian plantain) is a North American species of plants in the sunflower family.  It is native to the central and east-central United States primarily in the Appalachian Mountains, the Ohio/Tennessee Valley, and the Mississippi Valley.  There are additional populations in the east (New Jersey, Maryland, Pennsylvania, South Carolina) and farther west in Oklahoma.

Acolapissa: The Acolapissa were a small tribe of Native Americans.  Traditions have them living on the shores of the Pearl River, between Louisiana and Mississippi before 1702.  This made them one of four tribes, along with the Bayogoula, Biloxi, and Pascagoula who inhabited the Gulf coast of what is now the state of Mississippi at the time of the European arrival.  After that time, they moved farther west, into the area around the future New Orleans.  Pressured by European settlement of the area and disease, the small tribe eventually merged into the Houma, which now live in and around Houma, Louisiana.  Estimates put the current population of the Houma tribe at around 11,000 people.  The U.S. government denied a petition for Federal status for the Houma in 1994.

Sauromatum: Sauromatum is a genus of flowering plants in the family Araceae.  The genus is native to tropical Africa, tropical Asia, and the Arabian Peninsula.  Their inflorescences last for only a few hours to a day and give off an unpleasant smell.  The inflorescence disperses its odor by heating up.

Vancouveria: Vancouveria ( ) is a small group of plants belonging to the barberry family described as a genus in 1834.  The three plants in this genus are known generally as inside-out flowers, and they are endemic to the West Coast of the United States.  The genus was named after George Vancouver, English navigator and explorer.

Fort Harker (Kansas): Fort Harker, located in Kanopolis, Kansas, was an active military installation of the United States Army from November 17, 1866 to October 5, 1872.  The fortification was named after General Charles Garrison Harker, who was killed in action at the Battle of Kennesaw Mountain in the American Civil War.  Fort Harker replaced Fort Ellsworth, which had been located 1.6 km from the location of Fort Harker and was abandoned after the new fortifications at Fort Harker were constructed.  Fort Harker was a major distribution point for all military points farther west and was one of the most important military stations west of the Missouri River.

Register Cliff: Register Cliff is a sandstone cliff and featured key navigational landmark prominently listed in the 19th century guidebooks about the Oregon Trail, and a place where many emigrants chiseled the names of their families on the soft stones of the cliff it was one of the key checkpoint landmarks for parties heading west along the Platte River valley west of Fort John, Wyoming which allowed travelers to verify they were on the correct path up to South Pass and not moving into impassable mountain terrainsgeographically, it is on the eastern ascent of the Continental divide leading upward out of the great plains in the east of the U.S. state of Wyoming.  It is notable as a historic landmark for 'registering' hundreds of emigrants on the Oregon Trail (thus also the other northern Emigrant Trails that split off farther west such as the California Trail and Mormon Trail) who came to follow custom and inscribed their names on its rocks during the western migrations of the 19th century.  An estimated 500,000 emigrants used these trails from 1843–1869, with up to one-tenth dying along the way, usually due to disease.

Supporting paragraphs: Vancouveria Sauromatum
Answer: Vancouveria