Increased rates of self-fertilization (“selfing”) in sexual systems are tightly associated with an annual life history in flowering plants; we expect an increased selfing rate and morphological traits associated with selfing (“selfing syndrome”) to evolve in annual lineages. One key trait to measure here, of course, is the level of selfing. Selfing rates, however, are difficult to estimate––large progeny arrays are often unattainable for natural populations, and population genetic studies using the Inbreeding Coefficient to calculate selfing rates can be unreliable. To circumvent this problem, selfing rates can also be estimated from a population genomic value called the Identity Disequilibrium (g2), defined as the variance in inbreeding levels as measured by how much multilocus heterozygosity deviates from expectation under random assortment. Here, we test whether life history would give rise to differences in selfing rates among closely related annual and perennial, self-compatible species of genus Calyptridium Nutt. in the Montiaceae family. We sample 20-30 individuals from around 10 populations for two annual Calyptridium species and two perennial species across western North America. We utilize ddRAD sequencing and assemble the resulting reads using a closely-related whole genome reference to identify a large number of SNPs. The assembled ddRAD loci are then used to calculate g2 to estimate average population selfing rate, such that we can compare the values among populations, and importantly, between annual and perennial species. This is one of few examples utilizing high-throughput sequencing to comparatively and concurrently study selfing rates and plant life history. Furthermore, this provides an excellent population genomic dataset for ongoing conservation efforts in the genus Calyptridium.