Clonally propagated food crops are often by-words for non-adaptability and potential disaster - look at the potato famine in the mid-19th century, for example. Crop plants are also used as ‘model organisms’, and are often where evolutionary insights arise. The authors combine their in-depth research on cassava (Manihot esculenta, Euphorbiaceae) with the scattered and scarce literature on clonally propagated food crops to show that these crops merit more study from an evolutionary standpoint - there is more we don't know than has previously been considered. They propose that evolution in these crops has not been a simple capture of and selection for single desirable traits, but instead is a more complex process mixing clonal and sexual processes that generates a great deal of variation and accumulation of traits of interest. Reduction of sexual fertility in these crops, for example, is more complicated and more diverse than text book examples suggest. Clonal crop plants are clearly ripe for study, and will allow insights in diverse evolutionary questions as well as to agriculture and plant breeding. The development of effectively clonal crops using biotechnology is a feature of modern agriculture - this paper should be required reading for biotechnologists, as the evolutionary questions raised here will be of great interest. And finally, I really liked the way the authors emphasize the importance of cultural knowledge in crop evolution; far from being haphazard cultivators, local farmers use and improve clonally propagated plants in subtle ways - something that should be of as much importance as the evolutionary potential of the plants themselves.