When people refer to strains of marijuana, they often refer to them as either the sub-species Sativa, or Indica, because those are the most common types. There may be a third sub-species, however, that many people don't even know exist. This type of cannabis is called ruderalis, but there is an ongoing debate on whether ruderalis is a separate sub-species, or just an ancient blend of Indica and Sativa. It produces little yield and little to no THC, and it's a hardy type of cannabis that can thrive in the rough conditions of parts of China and Russia. Ruderalis differs from the other sub-species of cannabis in that it has the ability to autoflower, and it is also less likely to become infested with insects or succumb to a variety of diseases.
Because ruderalis is low in THC, a quality that has been praised in medical marijuana for offering relief while not providing psychoactive effects, the sub-species is experience a revived popularity among medical cannabis growers. Whaxy says, "If done properly, hybrid strains containing some ruderalis genetics can offer many of the best characteristics of sativa or indica strain combined with a solid amount of CBD and faster growth."
Visit Whaxy for a more in depth description about ruderalis and its history, as well as pictures of leaves to help you identify your sub-species and a list of strains that may contain at least some ruderalis.