Aside from creeping buttercup, other perennial species include R. occidentalis, the Western field buttercup, identifiable by long, three-lobed leaves extending from the base. R. acris, or Tall buttercup, reaches heights of 3 feet with 1-inch wide blooms. Birdfoot buttercup, R. orthorhynchus, grows to 24 inches and has distinctive achenes or fruit that appear straight and skinny verses hooked like most others.