Buterwort or Butterwort: How To spell?

The word Buterwort is misspelled against Butterwort, a noun meaning "A genus of low herbs (Pinguicula) having simple leaves which secrete from their glandular upper surface a viscid fluid, to which insects adhere, after which the margin infolds and the insects are digested by the plant. The species are found mostly in the North Temperate zone."