Two leaf-types occur in Mitrophyllum mitratum, succeeding each other in the annual growth cycle.
The first pair is only fused (connate) at the base, spreading opposite each other in a boat-shape, the leaves up to 6 cm long. In picture they are channelled above, rounded below and curving down to the pointed tip. Leaf texture is soft, very succulent and smooth.
The second, rounded to triangular leaf-pair grows from the gap between the first pair on a long, fused, stem-like section, about two thirds of its overall length. This part is nearly cylindrical, thickly succulent and ridged on the flanks; soon to dry out and become the woody stem for next year’s new growth to issue from the tip. Old leaf skins persist for some time in tattered, dry papery or parchment-like sheaths or fragments upon the new growth. At the top of the upper leaf body is an equal pair of elongated, pincer-like leaves, in-curving in the photo.
The phenomenon of dissimilar leaf types occurring in a plant is known as heterophylly.
When the upper leaf pair starts to develop, its rounded, twin-peaked structure resembles a bishop’s mitre, bringing the genus its name of Mitrophyllum. The specific name, mitratum, carries on in the same vein (Williamson, 2010; Frandsen, 2017; Smith, et al, 1998; Herre, 1971; iNaturalist).