The leaves on a young Senecio maritimus plant are often narrowly oblong, fleshy and slightly hairy below. The margins are rolled under. Even here some are wider, the rounded shapes difficult to label as obovate rather than ovate. The leaves rarely exceed 2,5 cm in length.
The leaf-bases taper to the stems, some slowly, without displaying clear petioles and somewhat stem-clasping. Bigger leaves seen elsewhere may be widely eared at the base, clarifying the sessile feature.
Some leaves are channelled above, more than only having sunken midribs (Manning, 2007; Manning and Goldblatt, 1996; Bond and Goldblatt, 1984; JSTOR; iNaturalist).