What does anaphora add to asyndeton?

Anaphora and asyndeton are both literary (specifically rhetorical) devices that have their origins in greek philosophers. Anaphora etymologically means "to bring back" and is contemporarily used to refer to the repetition of a word/phrase at the beginning of sentences or clauses. The rhetorical effect of this device is to emphasize and elicit an emotional response to particular concepts or ideas -- through subjecting memory to repetitious inscriptions  and the production of a pleasurable rhythm. The most famous example is the repetition of the "I" in the quote "I came, I saw, I conquered." In contrast, asyndeton etymologically means "unconnected" and is used in the present to refer to purposely missing conjunctions  -- such as: "but," "or," "and." The intended rhetorical effect is both to produce a dramatic aesthetic and to leave open a degree of semantic ambiguity. The same quote by Julius Caesar, "I came, I saw, I conquered," also is an example of an asyndeton - since there is no "and" before the last clause in the series. However, these two rhetorical devices are not in immediate conversation with one another. Anaphora is conventionally contrasted to epistrophe - referring to repetition that occurs at the end of a clause or sentence. Where, asyndeton is normally juxtaposed with the concept polysyndeton - which refers to the unnecessary use of conjunctions, when commas would suffice.