How do lenticels typically appear on the bark of a tree?

Lenticels are small, spongy openings in the bark of trees that allow for the exchange of gases between the inner tissues and the external environment. They typically appear as tiny polka dots or small stripes on the surface of the bark. This characteristic appearance is due to the structure of the lenticels, which are formed by groups of loosely arranged cells that create air spaces, giving them a distinctive pattern that can vary among species.

In contrast, smooth patches refer to areas on the bark that may not have those openings, which aren't indicative of lenticels. Raised bumps might describe some forms of bark texture but do not capture the appearance of lenticels accurately. Dark streaks could be mistaken for certain types of injuries or disease effects on tree bark, but they do not represent the gas-exchange structures of lenticels. The identification of lenticels based on their distinct appearance is important for understanding the physiological functions of trees and their adaptations to the environment.