The paper by Russell Lande and Douglas W. Schemske explores the evolution of self-fertilization and inbreeding depression in plants. They construct genetic models to explain how inbreeding depression changes with the mean selfing rate in a population, incorporating mutations to recessive and partially dominant lethal and sublethal alleles at multiple loci, as well as mutation in quantitative characters under stabilizing selection. The models help explain observations of high inbreeding depression (>50%) in primarily outcrossing populations and significant heterosis in predominantly selfing populations. The authors argue that predominant selfing and predominant outcrossing are alternative stable states of the mating system in most plant populations, with the stable state depending on the population's history and the magnitude of effect of genes influencing the selfing rate. They also discuss the role of environmental factors, such as pollinator failure and population bottlenecks, in promoting the evolution of self-fertilization. The models predict a bimodal distribution of selfing rates among plant species, corresponding to the two evolutionarily stable reproductive modes of predominant outcrossing and predominant selfing.The paper by Russell Lande and Douglas W. Schemske explores the evolution of self-fertilization and inbreeding depression in plants. They construct genetic models to explain how inbreeding depression changes with the mean selfing rate in a population, incorporating mutations to recessive and partially dominant lethal and sublethal alleles at multiple loci, as well as mutation in quantitative characters under stabilizing selection. The models help explain observations of high inbreeding depression (>50%) in primarily outcrossing populations and significant heterosis in predominantly selfing populations. The authors argue that predominant selfing and predominant outcrossing are alternative stable states of the mating system in most plant populations, with the stable state depending on the population's history and the magnitude of effect of genes influencing the selfing rate. They also discuss the role of environmental factors, such as pollinator failure and population bottlenecks, in promoting the evolution of self-fertilization. The models predict a bimodal distribution of selfing rates among plant species, corresponding to the two evolutionarily stable reproductive modes of predominant outcrossing and predominant selfing.