Despite their formidable names, polysyndeton and asyndeton are nothing more than different ways of handling a list or a series. Polysyndeton places a conjunction (and, or) after every term in the list (except, of course, the last). Asyndeton uses no conjunctions and separates the terms of the list with commas. Both differ from the conventional treatment of lists and series, which is to use only commas between all items except the last two, these being joined by a conjunction (with or without a comma--it is optional)."
(Thomas S. Kane, The New Oxford Guide to Writing. Oxford University Press, 1988)