Arrow Root, which is used in hoodoo for gambling luck and which was used by the Arawak natives to draw out the poison from arrow wounds, is mostly adulterated or even completely fake when bought in powder forms in stores. If the brand contains any real Arrow Root powder it is often cut with Casava or even cornstarch powder. Some stores do sell the whole root but it is too difficult to dry and powder on your own.
Chilies (what most people call "peppers") often have different names between the fresh and dried forms. For example, Chipotle is simply dried red Jalapeno peppers. Ancho chilies are dried Poblano, California chillies are dried Anaheim, and Cayenne peppers are dried Ginnie (Guinea) peppers. The last one has a major role in African-derived magical traditions as it is grown in Africa. The last one also became the name of a famous alternative rock group as another name for Cayenne pepper is "Red Hot Chili Peppers".
Grains of Paradise Seeds, a.k.a. Guinea Pepper Seeds, are unrelated to the Cayenne or Ginnie Pepper. Instead, they are related to Ginger and get their name from their similarity to black peppercorns.