What is the purpose of a spore?

Its the reproductive part of a fungi or a pteridophyta, fern. Might also be the reproductive part of other primitive plants, perhaps hornworts, liverworts, or horsetails also produce spores, I'm not sure, but I know for a fact that ferns do it, as well as all fungi. A spore is like a very small seed, produced in much greater quantity, without the resilliency that seeds have (no seed coat or extra nutrients for the growing organism).