[4] It can appear as a large continuous patch, a variegated or reticulated region, or as numerous small spots.
The primary function of the translucent windows is to increase the absorption of radiant energy, and thereby the rate of photosynthesis.
The windows focus and channel diffused light to the green photosynthesizing surface hidden inside the underground part of the plant.
It has been found in the Lithops species of succulents that leaf window size correlates inversely with habitat solar irradiance; plants growing in regions of high irradiance and low rainfall have smaller windows than those growing in cloudy, high-rainfall regions.
[7] The carnivorous cobra lily (Darlingtonia californica) uses fenestration to confuse insects and increase the effectiveness of its trap.