A different pollen signature, if you like, or a different pollen fingerprint.

Cool pollen, though.

That's a geranium pollen.

They get paid by pollen and nectar, to move that male sperm, the pollen, from flower to flower.

I am allergic to pollen.

They build up a static electric charge and the pollen jumps on them and helps spread that pollen from bloom to bloom.

But pollen forensics can be very subtle.

Jonathan Drori Every pollen grain has a story

Pollen is produced by the anthers of flowers.

But anyway, take a look at its pollen.

The fossilized pollen was not of savanna vegetation.

Probably you are allergic to pollen or dust.

Pollen is a flower's way of making more flowers.

So, that's 20 micrometers across, that pollen grain there.

But not all pollen is quite so simple looking.

Like I said, pollen carries the male sex cells.

And of course, they're made to carry this pollen.

First of all, pollen is tiny. Yes we know that.

The pollen has little barbs on it, if we look.

That tells me that it's actually been fossilized, this pollen.

And the reason for that is they've got to chuck out masses and masses of pollen to have any chance of the pollen reaching another plant of the same species.

Here is a scanning electron micrograph of a grain of pollen.

Now the way that plants transmit that information is through pollen.

That little hole in the middle there is for the pollen tube, and when the pollen finds its special female spot in another Morina flower, just on the right species, what happens?

My story is actually not about plant propagation, but about pollen itself.

Now, much of the pollen will still be there after repeated washings.

Pollen is tiny. It gets on to things, and it sticks to them.

The plant gets something, and the hawk moth spreads the pollen somewhere else.

And the plant showers them with pollen, and off they go and pollinate.

Most pollen that causes hay fever for us is from plants that use the wind to disseminate the pollen, and that's a very inefficient process, which is why it gets up our noses so much.

At night they get covered in pollen, which showers down over them, and then the bristles that we saw above, they sort of wilt and allow all these midges out, covered in pollen fabulous thing.

And it isn't just bright flowers that have pollen it's also trees and grasses.

Four very different habitats might look similar, but they've got very different pollen signatures.

It confused me why did these allergy symptoms persist well past the pollen season?

And there is as many different kinds of pollen as there are flowering plants.

And then they were so clever, they found a way to analyze fossilized pollen.

Each anther can carry up to 100,000 grains of pollen, so, it's quite prolific stuff.

This is a bee's leg with the pollen glommed onto it from a mallow plant.

Lots of evidence from sediment cores and the pollen types, oxygen isotopes and so on.

So, different species of plants grow in different places, and some pollen carries further than others.

The insects and other species can take the pollen, transfer it directly to where it's required.

This is the Monterey Pine, which has little air sacks to make the pollen carry even further.

This is some pollen embedded in a cotton shirt, similar to the one that I'm wearing now.

each of us, in fact, with a story to tell from the pollen fingerprint that's upon us.

So, not only does each type of pollen look different, but each habitat has a different combination of plants.