With lips, i.e. when a calyx or corolla is divided into two major parts, an upper and a lower.
Refers to the mint family’s (Labiatae) “lipped” petals. The tubular corolla is divided into two irregular parts, commonly with two lobes in the upper lip and three lobes in the lower lip.
It refers to a corolla with one or more petals formed into a lip.
With lips, usually when in zygomorphic flowers the corolla is divided into an upper and a lower part.