Apparently there's no notable distinction - to quote from the article, "Beyond the plant’s size, there’s no way to be certain that a Conophytum for sale in a plant store didn’t come from the wild. Conos quickly “shed the battle scars of nature”—sun-weathered leaves or dirt mounds". So on one side it's hard to tell if a plant is cultivated or poached (making it easy to obfuscate the origins of poached plants), and on the other side it takes decades to grow a plant to a size which makes it valuable (so poaching becomes attractive).