The lotus effect refers to the very high water repellence (superhydrophobicity) exhibited by the leaves of the lotus flower (Nelumbo

Nelumbo

Nelumbo is a genus of aquatic plants with large, showy flowers resembling water lilies, commonly known as lotus. The generic name is derived from the Sinhalese word Nelum. There are only two known living species in the genus. The sacred lotus is native to Asia, and is the better known of the two...

).
Dirt particles are picked up by water droplets due to a complex micro- and nanoscopic architecture of the surface, which minimizes adhesion.

This effect can easily be demonstrated in many other plants, for example Tropaeolum (nasturtium), Opuntia

Opuntia

Opuntia, also known as nopales or paddle cactus , is a genus in the cactus family, Cactaceae.Currently, only prickly pears are included in this genus of about 200 species distributed throughout most of the Americas. Chollas are now separated into the genus Cylindropuntia, which some still consider...

(prickly pear), Aquilegia

Aquilegia

Aquilegia is a genus of about 60-70 species of perennial plants that are found in meadows, woodlands, and at higher altitudes throughout the Northern Hemisphere, known for the spurred petals of their flowers.-Etymology:The genus name Aquilegia is derived from the Latin word for eagle , because...

(columbine), cane, and on the wings of certain insects.

The phenomenon was first studied by Dettre and Johnson in 1964 using rough hydrophobic surfaces.