If you've ever made a spore print of a toadstool, then you might like to try making a similar one for a fern. This is one I made last night, from a piece of a Dryopteris fern growing in our garden.
All you need to do is to find a fern frond with sporangia ripening on its undersurface, like the one below.
This one is a little too young - you need to find one where the little grey, kidney-shaped cover (called indusium) over the sporangia has begun to shrivel and split and you can seen the dark sporangia around the edge. A magnifying glass is helpful for this.
Then all you need to do is to leave the frond, sporangia-side downwards, on a sheet of white paper overnight, preferably in a room with no draughts. Overnight the sporangia will catapult their spores out, leaving an impression of the frond as they settle.
The best thing to do with the spore print is to photograph it - it smudges of you try to make it permanent with an aerosol fixative.
Or you could sow the spores, which will germinate to produce hundreds of new ferns - click here to see how this happens. I find the best substrate to sow them on is a piece of rotten wood that has been boiled in water to sterilise it. When it's cool sprinkle the spores on the surface of the wet wood and keep it permanently moist - a green film of germinating spores will appear over the surface and eventually produce ferns.
Take care not to breath in the spores, which are as fine as dust and can be an irritant.