black-eyed Susan

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of several North American herbs of the genus Rudbeckia in the composite family, especially R. hirta, having hairy stems and leaves and showy flower heads with orange-yellow rays and dark purple or brown centers.
• noun A tropical African twining herb (Thunbergia alata) cultivated for its showy, usually yellow to orange tubular flowers with dark purple centers.

from The Century Dictionary.

• One of several plants having flowers or heads with a dark center.

from the GNU version of the Collaborative International Dictionary of English.

• The coneflower, or yellow daisy (Rudbeckia hirta).
• The bladder ketmie.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A flowering annual plant Rudbeckia hirta; the state flower of Maryland.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun annual weedy herb with ephemeral yellow purple-eyed flowers; Old World tropics; naturalized as a weed in North America
• noun tropical African climbing plant having yellow flowers with a dark purple center
• noun the state flower of Maryland; of central and southeastern United States; having daisylike flowers with dark centers and yellow to orange rays