Abstract
A new species of Senecio section Adamantina is here described as Senecio hortensiae (Senecioneae, Asteraceae), an endemic species from Parque Nacional dos Pontões Capixabas, Espírito Santo state, Brazil. This new species is recognised by the sessile leaves densely clustered at the median part of the stem and by the radiate capitula in a terminal lax panicle. It is closely related to Senecio graciellae but differs basically by the size and margins of the leaves, capitulescence and number of ray florets. Illustrations, comments, distribution map, and conservation status are provided for the new species. Additionally, a diagnostic key to the species of Senecio section Adamantina is provided.