Marshallia grandiflora, the Appalachian Barbara's buttons, is an extinct species of flowering plant in the genus Marshallia within the sunflower family.

It was endemic to the Blue Ridge Mountains of North Carolina in the Eastern United States, in Henderson and Polk counties.

It was found primarily along gravelly and sandy bars along high-gradient rivers, and was presumably wiped out due to changes in this restricted habitat.

[3][4] Marshallia grandiflora was an herb up to 90 cm (3 feet) tall.

[5] It was formerly considered conspecific with M. pulchra, the beautiful Barbara's buttons or Monongahela Barbara's buttons, which is endemic to the central Appalachia region from southwestern Pennsylvania to eastern Tennessee, with the largest population occurs along the Gauley River in West Virginia.