Stomata consist of specialised cells that mainly occur on the underside of leaves. They regulate the gas exchange between the plant and it’s environment, the plant is 'breathing' through them, as it were. Stomata are very recognizable by the two bean-shaped guard cells that regulate the size of the opening.

Diatoms are brown microalgae that can be found in all freshwater and marine environments. They are an important link in the ecological cycle. In streams and rivers you often see stones covered with a brown layer that is formed by diatoms.

Pollen is a fantastic subject to study with a microscope. The diversity of shapes of pollen grains is enormous and a lot of interesting information can be derived from it.