Rub the leaf and inhale the fragrance, Michaelus Tracey is saying.

The musky scent of this cannabis plant is distinctly different from the citrusy aroma of another that he is also holding.

To the untrained eye, the neat rows of flowering cannabis crops in front of us are indistinguishable from each other.

Yet master cultivator Tracey can identify the separate varieties by their smell and the shape of their leaves.

Nine strains are being grown here at Pineapple Road, a farm deep in the countryside on the Caribbean island of Antigua. The warm temperatures, abundant sunshine, and high humidity make this prime territory for growing the plants.