Senecio maritimus flowerheads grow in loose clusters (or few-flowered corymbs) at stem-tips. The heads have long, cylindrical and sturdy peduncles.

Apart from the dark tips of the single row of involucral bracts, there are occasional dark markings near the base of an involucre, indicating the presence of one of the few bracteoles that also have dark tips. They end at the base of the head.

The floral discs protrude slightly above the spreading rays, more so once the stamens and styles of the disc florets are exserted.

Flowering happens from late winter to early summer. The photo was taken in September (Manning, 2007; Manning and Goldblatt, 1996; Bond and Goldblatt, 1984; JSTOR; iNaturalist).