I've been in and out of Cambodia since 2002. The grass sold in the touristic areas are hybrids from the states, grown from Cambodian deportees organisation. So if someone wants to find the pure sativa of Cambodia, is to get it from old bong smokers above sixty years old and it's pretty much like trying to find a unicorn. The younger generation in Cambodia just drink and smoke ice(methamphetamine).
p.s.: my first time back to Cambodia was in 1992. At that time, I went to Orussey Market in Phnom Penh and bought a kilo of pure brown sativa for $2.00.