Only within the last 10,000 years have men and women relied on agriculture and the domestication of animals in order to make a living. 1 One can guess that during most of that time humans have tried, through various means, to influence the forms of the plants and animals kept for sustenance, power, companionship, and decoration. From the first time a farmer noticed a plant bearing larger or earlier fruit and tried to increase the occurrence of that plant, we have had avid plant enthusiasts among us.