Oh this was a neat paper!
Some things to note:
Roots contained between 0.001% and
0.004% cannabinoids in all three chemovars (Supplementary Table 10), which agrees with the minuscule amounts reported by other studies (0% and 0.03%)5,29.
Stem barks contained between 0.005% and 0.008% cannabinoids in all three chemovars and was found to be less than the amounts previously reported (0.02% and 0.1–0.3%)5,29.
Total cannabinoids quantified in leaves were between 1.10% and 2.10%, which agreed with the
previously-reported amounts (1–2% and 1.40–1.75%)29,53 but not others (0.05%).
Mono- and sesquiterpenoids were not detected in stem barks or roots.
Total mono- and sesquiterpenoids ranged from 0.125% to 0.278% in leaf and 1.283% to 2.141% in inforescence in the three chemovars (Supplementary Table 12), which were less than the 4% reported in unfertilized fowers in a previous study, 5.
Total sesquiterpenoid content was higher than total monoterpenoids in fan leaves in Chemovar I and Chemovar II but was comparable in Chemovar III. This observation was clearer when contents were expressed as ratios: sesquiterpenoids comprised approximately 90% of total terpenoids in Chemovar I and II and comprised 53% of the total terpenoids in Chemovar III.
- Russo, E. B. & Marcu, J. Cannabis Pharmacology: Te Usual Suspects and a Few Promising Leads. in Cannabinoid Pharmacology
67–134 Elsevier, https://doi.org/10.1016/bs.apha.2017.03.004 2017
- Upton, R. et al. Cannabis inflorescence: cannabis spp.; standards of identity, analysis, and quality control. (American Herbal
Pharmacopoeia., 2014).
- Flores-Sanchez, I. J. & Verpoorte, R. Secondary metabolism in cannabis. Phytochemistry Reviews 7, 615–639 (2008).
So it looks like stems and roots are basically worthless… Missing half the terpenoids and all flavanoids and the overall content is so low as to make extraction likely not worth the effort. Leaves however seem worth it as you still get the sterols and triterpenoids that you’d get in the root/stembark but at a higher percentage 
This was also neat!
Several chemotaxonomic studies utilized this method to discriminate “Sativa” and “Indica” varieties and found that terpenoid profles are uniquely retained from their respective landrace ancestors48–50,56,58,59. The presence of more hydroxylated terpenoids in Chemovar III does not ft its reported classifcation as C. indica ssp. indica (NLD, vernacular “Sativa”), but more closely aligns with C. indica ssp. afghanica (WLD, vernacular “Indica”). Similarly, although the Chemovar I and II were reported as “Indica,” their terpenoid profles were characteristic of “Sativa” chemovars. One study found that the reported ancestry percentages of “Sativa” vs. “Indica” for 81 drug-type chemovars are only moderately correlated with the calculated genetic structure68, indicating that the vernacular classifcations do not reliably communicate genetic identity. For medicinal research and applications, cannabis chemovars should be identifed by their chemical fngerprints, which are more reliable than their names48,49,56.
- Hazekamp, A. & Fischedick, J. T. Cannabis - from cultivar to chemovar. Drug Testing and Analysis 4, 660–667 (2012).
- Fischedick, J. T. Identifcation of Terpenoid Chemotypes Among High (-)-trans-Δ9-Tetrahydrocannabinol-Producing Cannabis
sativa L. Cultivars. Cannabis and cannabinoid research 2, 34–47 (2017)
- McPartland, J. M. & Guy, G. W. Models of Cannabis Taxonomy, Cultural Bias, and Conficts between Scientifc and Vernacular
Names. Te Botanical Review 4, 327–381 (2017).
- Hillig, K. W. Genetic evidence for speciation in Cannabis (Cannabaceae). Genetic Resources and Crop Evolution 52, 161–180
(2005).
- Fischedick, J. T., Hazekamp, A., Erkelens, T., Choi, Y. H. & Verpoorte, R. Metabolic fingerprinting of Cannabis sativa L.,
cannabinoids and terpenoids for chemotaxonomic and drug standardization purposes. Phytochemistry 71, 2058–2073 (2010).
