Ruderalis

Cannabis ruderalis is a hardy subspecies native to regions with short summers, such as Russia and Central Asia. Its defining feature is that it flowers based on age rather than light cycle — an adaptation to long northern daylight. On its own ruderalis is low in THC, but breeders crossed it with potent indica and sativa lines to create modern autoflowers, which inherit the automatic flowering trait while reaching 20%+ THC.