No other group of plants produces such a pollen grain.

It is possible to identify a plant species from its pollen grain.

The ship seemed like a pollen grain lost in a giant forest.

Pollen grains seem to have a 'narrow window of opportunity' in which they will grow.

This is a method in which pollen grains are stored.

It describes how the pollen grains get to the female parts of a plant.

In the fossil record we find only this protective wall of the pollen grains.

These pollen grains are digested fully between 6 and 28 hours.

If the temperature is over 90 degrees, pollen grains are only viable for 24 hours.

They contain pollen grains, which tell you what vegetation grew in the area over the years.

This led to the discovery that all pollen grains in a species were alike.

Trapped pollen grains show the types of vegetation that lived in the area.

A typical example would be a pollen grain in a beaker of water.

These support the development of microspores into mature pollen grains.

Each individual plant can produce 4 to 5 million individual pollen grains.

Individual pollen grains are small enough to require magnification to see detail.

Pollen grains provide the signature of particular flora for this scheme.

Some pollen grains will land on a female cone for pollination.

Pollen grains stick to the stigma, the female organ of a plant.

Go outdoors after a rain shower, while the pollen grains are still stuck to the ground.

The only missing piece of evidence: preserved pollen grains.

The pollen grains are then examined under a microscope, counted and identified.

The oldest known fossils from flowering plants are pollen grains.