I understand where you're coming from. This is actually fairly interesting. Here's a thesis written by a guy with access to GW Pharma.
He identifies the ability to procure CBC and/or CBG rich concentrates via bubble bags by filtering out the larger heads and capturing the 25 micron from plants in early veg. They did this test with 178 plants from a 'variety of sources' and found that CBC was the most prominent in 4.5% and second most prominent in 78%. I guess that makes me wrong then, maybe it's CBG that's easier to procure. Not long after this discovery GW Pharma patented this process for procuring CBC including further purification.
http://www.google.com/patents/US20110098348
http://www.scribd.com/doc/214031988...of-Cannabis-Sativa-l-as-a-Phytopharmaceutical
(The Patent is by E.P.M. deMeijer from GW, the PHD thesis is from David Potter at GW. I have original copies of both, the thesis is hard bound.)
And this:
Euphytica (2009) 165:293–311
The inheritance of chemical phenotype in Cannabis sativa L. (III): variation in cannabichromene proportion.
E. P. M. de Meijer · K. M. Hammond ·
M. Micheler
-SamS
Last edited: