Ligulate: With a ligule; strap-shaped.*
Each ‘petal’ on these flower heads is, in fact, a tiny separate flower called a ray floret. Each ray floret produces a long, yellow strap (ligule) to help guide pollinating insects toward the fertile disc florets that make up the centre of the flower head. This plant belongs to the genus Ligularia which gets its name from its ligules.
*Harris, J.G., Harris, M.W. (2001). Plant identification terminology: An illustrated glossary (2nd ed.). Spring Lake: Spring Lake Publishing.