What is the name of the broad expanse of flat land in the western United States and western Canada  where the species of plant called the Polygonum sawatchense of the buckwheat family be found?
Great Plains The Great Plains (sometimes simply "the Plains") is the broad expanse of flat land (a plain), much of it covered in prairie, steppe and grassland, that lies west of the Mississippi River tallgrass prairie states and east of the Rocky Mountains in the United States and Canada. It embraces
Spiraea splendens Spiraea splendens is a shrub of the Rose Family (Rosaceae) native to the western mountains of North America, from California to British Columbia, commonly known as dense-flowered spiraea, rose meadowsweet, rosy spiraea, subalpine spiraea, and mountain spiraea. It is commonly found at elevations between 2,000 and 11,000 feet on inland mountain ranges. The plant is adapted to cold, moist, rocky slopes, subalpine forests and meadows.