Ranunculus aestivalis

Ranunculus aestivalis is a rare species of buttercup known by the common names fall buttercup and autumn buttercup. It is endemic to the state of Utah in the United States, where it exists only in Garfield County next to the Sevier River. It is restricted to a moist microhabitat in an otherwise dry, open ecosystem, and the amount of available habitat is very limited. This is a federally listed endangered species of the United States. It has been described as "the most graceful and showy members of the genus in the western United States," but also "one of the state's rarest and most restricted plants." This plant is often treated as a variety of Ranunculus acriformis or Ranunculus acris. A genetic analysis study showed it to be sufficiently separate and it was elevated to species status by one group of authors in 1994....read more on Wikipedia.