Now, pollen from plants, which are wind dispersed like trees and grasses and so on tend to cause the most hay fever.

The competition of grasses, right?

The weight of males varies from , and that of females from .

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

Allergy to pollen Nasal allergy to pollen is called pollinosis, and allergy specifically to grass pollen is called hay fever.

That's a geranium pollen.

But anyway, take a look at its pollen.

Cool pollen, though.

I am allergic to pollen.

I am allergic to pollen.

Tom has a pollen allergy.

Tom has a pollen allergy.

And remember that all our cereal crops are grasses as well.

Perhaps there's more pollen in the city.

The sandy desert surrounding the city supports wild grasses and occasional date palms.

Jonathan Drori Every pollen grain has a story

The fossilized pollen was not of savanna vegetation.

Diet The tortoises are herbivores that consume a diet of cacti, grasses, leaves, lichens, and berries.

) Caterpillars resemble those of the Danainae and feed on Apocynaceae.

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

Melissopalynology the study of pollen and spores found in honey.

They are herbivorous, feeding mostly on leaves and shoots, grasses, and sedges in particular, but also on roots and bulbs.

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.

This is how the prairies were built, the relationship between bison and grasses.

In tundra, the vegetation is composed of dwarf shrubs, sedges and grasses, mosses, and lichens.

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

But not all pollen is quite so simple looking.

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

Their diets consist mainly of grasses, as well as other plants and lichens.

So, what are pollen's properties? I hear you ask.

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

But pollen forensics can be very subtle.

Bees help plants spread their pollen.

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

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

With the trains coming in to urban hubs, they can carry pollen with them, very light pollen, and it's just a big supermarket in the city.

Other dicotyledons and monocotyledons have monosulcate pollen, or forms derived from it, whereas eudicots have tricolpate pollen, or derived forms, the pollen having three or more pores set in furrows called colpi.

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.

Like I said, pollen carries the male sex cells.

Wombats, on the other hand, live on the ground and feed on grasses, sedges and roots.

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

Books are the bees that carry pollen from one mind to another.

The Mittalmar is described as raised above the promontories , and as a region of grasslands, pastures and low downs with few trees.

The Poaceae (also called Gramineae or true grasses) are a large and nearly ubiquitous family of monocotyledonous flowering plants.