// Who He Is
Robert Connell Clarke is one of the most important figures in cannabis science. He is the author of "Marijuana Botany" — a foundational text on cannabis plant biology — and "Hashish!" — the definitive history and science of hashish production worldwide. With co-author Mark Merlin, he spent 17 years writing "Cannabis: Evolution and Ethnobotany," published by the University of California Press, Berkeley. He has travelled to every major hash-producing region on Earth, and his photographs of trichomes appear on the cover of the second edition of "Hashish!"
// On Hash Church
Clarke's first appearance on Hash Church in Episode 13 was a landmark moment for the show — bringing peer-reviewed, university-press-published scholarship into the weekly roundtable for the first time. He laid out his two-species cannabis taxonomy, explaining that the industry's use of "sativa" and "indica" is botanically backwards: Cannabis sativa is European hemp, while all drug cannabis — regardless of leaf shape or effect — is Cannabis indica. He subdivided indica into Narrow Leaf Drug (NLD, what consumers call "sativa") and Broad Leaf Drug (BLD, what consumers call "indica"). He also publicly corrected his own earlier work, changing "calyx" to "bract" and demonstrating his principle that "science is a work in progress."
// Key Contributions
Beyond taxonomy, Clarke introduced the Cannabis DNA Genome Project — using Next Generation sequencing to analyse approximately 1,000 dispensary samples alongside DNA from old land race seeds. He emphasised the urgency of preserving land race genetics before hybridisation erases them permanently, and called for collectors to share their old seeds for DNA extraction. His statement that "nothing truly tests above about 20% THC" challenged inflated lab results across the industry. Clarke returned for subsequent episodes (016, 017), continuing to shape the scientific foundation of Hash Church's discussions.