A Trichome is an epidermal "hair". Trichomes can be singular or multicellular.

A major function of the trichome is thought to be in plant defense against insects.

Chemicals produced in the glandular tip can deter feeding or the trichome can physically prevent the insect from reaching and feeding on the leaf.

Photo of a trichome.

Look close and you can see the tiny hairs (trichomes) on the back of these tomato flowers. There is some evidence that some types of chemicals produced in tomato trichomes can prevent insect attack.

Two photos, the first pointing out the tiny hairs (trichomes) on the back of tomato flowers, the second showing these trichomes enlarged.

Trichomes can appear as singular "hairs" or they can be branched as seen in these two stellate trichomes. Trichome shape is indicative of a particular plant species and has been used in taxonomy to identify plants.

Photo showing examples of single trichomes.

Single trichomes

Photo showing examples of branched trichomes.

Branched trichomes

Photo showing examples of stellate trichomes.

Stellate trichomes

Using an electron microscope you can see the beautiful shapes of trichomes.

An electron microscope image showing trichomes with and without glandular tips.

Trichomes contain many different types of secondary chemical products. Some are useful products like fragrances or flavors as in mints.

Trichomes also function to shade the leaf for plants native to hot, arid climates.

An electron microscope image of trichomes.

Trichomes grow from epidermal cells and can make striking patterns on leaves and stems like on this begonia leaf.

Close up photo showing patterns formed by trichomes on a begonia leaf.

Trichomes can also contain irritants that cause rashes in people like this stinging nettles (Urtica dioica).

These trichomes actually inject irritating chemicals into the skin when touched causing the "sting".

Photo of stinging nettles (Urtica dioica) plant.

Some plants like this fuzzy Kalanchoe have leaves covered with hairs (trichomes).

This may shade the leaf and make it more adapted to a hotter, drier climate.

Photo of the fuzzy leaves of the Kalanchoe plant.

The most specialized trichomes are found in insect eating plants like this sundew (Drosera). The trichomes glisten with exudate that trap and digest the insect (arrow) while the leave curls around it.

Photo of a sundew (Drosera) plant wrapping around an insect.

Close up photo of the trichomes of a sundew (Drosera) plant.

Tradescantia stamen hairs are large trichomes.

Stamen hairs are made of 10 to 30 large cells connected end to end.

Close up photo of a Tradescantia flower pointing out its stamen hairs.

Close up photo of a Tradescantia flower pointing out its stamen hairs.

Trichomes are very active cells. In stamen hairs of Tradescantia, it is easy to see this activity.

The cellular components move around the cell in strands of cytoplasm.

The cytoplasm is in strands that move around the vacuole near the outside of the cell along the cell wall.

Photo showing trichomes at the cellular level.

Cytoplasmic streaming in Tradescantia stamen hairs.

Click the image to see the movie.