Dr Leon Perrie
So a spore is the product of meiosis. In ferns it’s tiny, if you think of a ruler and think how big a centimetre is and divide that by ten then you've got a millimetre and then divide that by ten again and then halve it that is about the size of the spore.
Video: © University of Waikato
Micrograph of spore, Australasian Pollen & Spore Atlas, Creative Commons 3.0