bullation

Bullation is a term used to describe the appearance or formation of blister-like protrusions or a puckered, bubbled texture on a surface. The concept is most commonly encountered in botany, where a bullate or bullated leaf surface features raised blisters that give the leaf a wrinkled, cushion-like texture. These blisters result from air spaces between the epidermis and the underlying mesophyll, or from differential growth, hydration changes, or developmental constraints. The word derives from Latin bullatus, meaning blistered or inflated.

In botany, bullation can affect leaves, petals, or other plant parts and may influence texture, light reflection, and identification of particular taxa. Bullate surfaces are often described in plant descriptions to convey a diagnostic, tactile, and visual characteristic that helps distinguish species or varieties.

Beyond plants, bullation is used less consistently in geology and materials science to refer to surfaces that display bubble-like relief or embedded voids. In ceramics, polymers, and related fields, processes that trap gas or promote foaming can produce bullated surfaces, resulting in rounded, dome-like features on the exterior.

Overall, bullation describes a texture characterized by blister-like undulations or elevations arising from internal spaces, growth patterns, or manufacturing processes. Related terms include bullate and blister, with usage varying by discipline.