The simple, stalked leaves of Jamesbrittenia jurassica grow on trailing stems. Jamesbrittenia leaves are usually opposite but these in the photo appear as if they may be alternate.
The leaf-shape is ovate to oblong, the margins deeply lobed and irregularly toothed. The dark green to dull green blades have a covering of hairs, some glistening, glandular ones (Manning, 2009; iNaturalist).