Disk-floret of the Senecio (Longitudinal Section)
An longitudinal section view of a disk-floret of the senecio flower. Senecio is a genus of the daisy family (Asteraceae) that includes ragworts and groundsels. The flower heads are normally rayed, completely yellow, and the heads are borne in branched clusters. Though of late the genus has been reviewed and split up, it still contains a vast number of species (about 1,500) of extremely wide form including leaf succulents, stem and tuber succulents, annuals, perennials, aquatic forms, climbers, shrubs and small trees. Some species produce natural pesticides (especially alkaloids) to deter or even kill animals that would eat them.
Benson John Lossing, ed. The New Popular Educator (London, England: Cassell & Company Limited, 1891)