The flowerhead of Senecio maritimus comprises about eight spreading, yellow rays and a dense yellow disc in its centre. The ray tips curve back, the rays shaped close to oblong and slightly uneven.

The green base of the involucre is formed by one row of cohering narrow bracts.

The rope-like rolled up rays in the half-open buds in picture form interesting patterns for a while (Manning, 2007; Manning and Goldblatt, 1996; Bond and Goldblatt, 1984; iNaturalist).