Marijuana plants are grouped into 3 categories: Sativa, Indica, and Hybrid. A hybrid is a combination of Sativa and Indica. Sativa is an upper strand whilst indica is a downer. These 3 categories are then divided and categorized more into different strains. Strains are minor differences in how you feel when you use Cannabis. Some of the most famous and well-known strains of marijuana are: Acapulco Gold, Gelato, Grape Ape, White Widow, Purple Haze, Skunk and G13.