Oh and on the animals mother protecting offspring maybe I should say she either carries them, lays them in a safe area (as sea turtles think they are doing) or produce so many offspring that mutation wouldnt matter. However still those producing mass offspring (cause a plant does the same in a sense) either biologically "empower" the offspring's chances of survival to external stimuli thru years of evolution or instinctively tend to still place offspring in a safe location. Therefore in animals the offspring is fitted with every possible chance of protection available by the environment to the parent. Plants like marijuana wouldnt have that luxury of selecting a perfect area to place their offspring. So over the eons as marijuana spread worldwide naturally and by mans hand it constantly encountered new environments. Since the plant has no control of the environment its offspring will be in it has to provide the maximum protection it can.