Cannabis Sativa L. - Botany and Biotechnology is a collection of clinical studies coming out next month that fills up nearly 500 pages. The collection includes Dr. John M. McPartland's "Cannabis sativa and Cannabis indica versus 'Sativa' and 'Indica'" in which he said "distinguishing between 'Sativa' and 'Indica' has become nearly impossible because of extensive cross-breeding in the past 40 years. Traditional landraces of 'Sativa' and 'Indica' are becoming extinct through introgressive hybridization."
Dr. McPartland proposes "solutions for reconciling the formal and vernacular taxonomies," but it certainly calls into question the distinct personal traits often used to describe the difference between the two cannabis types. The author notes a difference exists—"phytochemical and genetic research supports the separation"—but their "nomenclature does not align with formal botanical C. sativa and C. indica based on the protologues of [famed botanists Carl] Linnaeus and [Jean-Baptiste] Lamarck."
In a 2016 interview for the Cannabis and Cannabinoid Research journal, Dr. Russo said, "There are biochemically distinct strains of Cannabis, but the sativa/indica distinction as commonly applied in the lay literature is total nonsense and an exercise in futility. One cannot in any way currently guess the biochemical content of a given Cannabis plant based on its height, branching, or leaf morphology. The degree of interbreeding/hybridization is such that only a biochemical assay tells a potential consumer or scientist what is really in the plant."
Dr. Russo—who adds that some people believe in a single species, while others describe up to four (sativa, indica, ruderalis and afghanica or kafiristanica)—suggests it's futile to apply simple descriptions to complex botanical systems. He adds that many strain characteristics are more closely tied to terpenes, which are less commonly analyzed. For example, he attributes the sedation associated with indica to a strain's myrcene content, while limonene provides the mood lift associated with sativa.
Testing can provide information on how much hybridization a plant experienced, but for the sake of detailing specific traits, "complete and accurate cannabinoid and terpenoid profiles" should be made available.
"I would strongly encourage the scientific community, the press, and the public to abandon the sativa/indica nomenclature and rather insist that accurate biochemical assays on cannabinoid and terpenoid profiles be available for Cannabis in both the medical and recreational markets," Dr. Russo added in the interview. "Scientific accuracy and the public health demand no less than this."