The leaves of Osteospermum oppositifolium are opposite as the name says and sessile (stalkless).
The leaf-shape is narrowly elliptic to oblanceolate, often with slight deviations from symmetric. The base tapers, the tip is acutely pointed, the margins entire. The fleshy blades are dull grey-green to blue-green and hairless but covered in a grey bloom (Le Roux, et al, 2005; Manning, 2009; Manning and Goldblatt, 1997; iNaturalist).