The sometimes wavy leaves of Protea acaulos are arranged on one side, the upper side of the stems. (Such an arrangement is described as secund.) The base of the petioles sprouting from all sides of the stem in this species will twist around the stem where necessary to point all the leaves straight up or nearly so. When stems are angled upwards, the leaves may, however, be found ascending up the stem, although this is not often seen.
Leaf shape is narrowly oblanceolate or spoon-shaped to broadly obovate. The leaf base tapers variably, the tip is rounded or pointed. A leaf may become 25 cm long.
Leaf surfaces are hairless, hard and leathery. The leaf midrib is red or creamy white and prominent, the ascending lateral veins visible and the margin entire, often red (Manning, 2007; Rebelo, 1995; Rourke, 1980; iNaturalist; Wikiwand).