Ruderalis cannabis is like sativa/indica. On it's own it's basically autoflowering hemp [flowers on age]

Autoflowering strains have ruderalis in them, so they flower after they been alive for a certain amount of time, not going on the light cycle. Lowryder is a perfect example of a strain that can flower under 24 hours of light, although it's best to have an 18/6 cycle all the way through seedling/veg and flowering of auto plants.