a lichen growth form; thalli leaf-like, flattened, with both an upper and a lower surface; usually attached to the twig by rhizines which grow from the lower surface, see Figs. 10 &: 12, pp. 15 & 17.
A lichen growth form with dorsiventral lobes (having upper and lower surfaces), usually loosely to tightly appressed to the substrate, 2-dimensional or weakly 3-D.