<jats:p> An examination of Erechtites hieracifolia (L.) Raf., during which two alkaloids have been isolated, has emphasized the close chemical relation which the genus Erechtites bears to Senecio. The chief alkaloid, hieracifoline, C<jats:sub>18</jats:sub>H<jats:sub>25</jats:sub>O<jats:sub>5</jats:sub>N, on hydrolysis yields retronecine and hieracinecic acid. The alkaloid is therefore of the type generally elaborated by Senecio species.