The simple leaves of Jamesbrittenia pristisepala are mostly opposite, only growing alternate among the flowers. The leaves are deeply lobed to near the midribs or here almost like rachises, the lobe margins large-toothed. The leaf appearance is more like brush than blade, the overall shape more ovate than elliptic. The leaf colour is greyer than green under a covering of glands or glandular hairs. Leaf dimensions are 10 mm to 30 mm long and 5 mm to 17 mm wide (Manning, 2009; Pooley, 1998; iNaturalist).