Resupinate

Resupinate is an adjective used in biology to describe bodies, structures, or forms that are turned upside down or that lie flat against a surface with the functional surface oriented away from the substrate. The term derives from Latin resupinus, meaning turned back or turned downward.

In mycology, resupinate fungi have crust-like, flattened fruiting bodies that are seated directly on the substrate and lack a distinct stalk or cap. The hymenial surface—the spore-producing layer—is exposed on the outward-facing surface, enabling spore release directly from the surface in contact with air. This growth form is one of several major fungal morphologies, contrasting with pileate (button-like) or effused-poroid forms.

In lichenology, a resupinate growth form refers to crustose lichens that spread flush against the substrate, with no elevated lobes or differentiated thallus margins. These lichens are often firmly attached and can be readily confused with simple films or stains on rocks, bark, or soil.

The term can also appear in other biological contexts to describe inverted or flat-lying structures, but in practice it principally denotes crust-like growths on substrates in fungi and lichens. Etymology: from Latin resupinus, meaning turned back or turned downward.