We’re sorry to break it to you but Indica, Sativa, and Hybrid labels don’t matter that much. They’re not accurate from a plant biology standpoint nor do they have any scientific meaning. Don’t kill the messenger.
“Sativa” and “Indica” have confusing origin stories. We need to venture back to 1753 for a moment; this was the first time Cannabis Sativa was officially documented and classified as a species of the genus Cannabis, which stems from the plant family Cannabaceae.
Carl Linnaeus, a Swedish botanist known as the "father of modern taxonomy" who formalized a system for naming species, described the Cannabis species in his book Species Plantarum (1753). It was thought that only one species of Cannabis existed; Cannabis Sativa L. The “L” stands for Linnaeus; and this is still believed to be accurate.
Thirty years later, an eminent French biologist, Jean-Baptiste Lamarck, got his hands on some plant specimens collected in India. Based on the specimens’ thicker stems and the shape of their leaves and flowers, he proposed that there are in fact two species of Cannabis: Cannabis sativa, the species mainly cultivated in Europe, and Cannabis indica, a wild species growing in India and neighboring Asian countries; this is now thought to be incorrect. During this early stage of plant taxonomy, scientists were often forced to reach conclusions on the basis of very limited material.
In 1924, a Russian botanist named Dmitri Yanishevski identified yet another potential “species” which he named Cannabis ruderalis, known for being a shorter plant that reaches maturity quickly due to adapting to shorter summers of the region. Yanishevski himself was not totally convinced that the phenotypic differences he observed justified a new species.
This all begs the question: Does the genus Cannabis contain a single species or is it correct to recognize separate species i.e. sativa, indica, ruderalis?
It seems accurate that Cannabis is a monospecific genus, meaning all Cannabis plants that display different morphological characteristics (phenotypes) are just varieties of a single species. Those varieties can then be grouped into subspecies based on sharing those distinct characteristics, whether morphological and/or chemical.
As far as impacting the psychoactive effects experienced when consumed, “Sativa”, “Indica”, and “Hybrid” labels on modern, cultivated varieties have no logical standardization or scientific backing to determining any distinct effects. “Strain” names are equally meaningless and really only serve marketing purposes.
Ultimately, the effects of Cannabis are determined by the compounds present in the flower, mainly cannabinoids, terpenes, and flavonoids, the quality of the flower, and the context in which the flower is consumed—who’s consuming it, how it’s being consumed, how much of it is consumed, and the environment it’s consumed in.