The type specimen was collected by the first author from a Caribbean lowland rainforest in the Indio Maíz Biological Reserve (San Juan River).

[2] Malmidea cineracea grows on bark and has a granulose-isidiate texture with a greenish-grey colour, appearing dull on a whitish, fibrous base layer, and is about 150–200 μm thick.

The hymenium is approximately 80 μm high, hyaline, and turns blue when stained with iodine; it contains simple paraphyses that are not thickened at the tips.

[2] No conidiomata have been observed to occur in this species, and thin-layer chromatography reveals no substances except for thin bands of terpenoids, likely originating from the bark.

The former species, found in the Amazon rainforest of Bolivia, can be distinguished by its abraded margin, which internally contains yellowish-brown granules that are unreactive when treated with potassium hydroxide (K−).