Do the apple and crabapple trees in Boulder County reflect multiple independent introductions of apple trees? We hypothesized that the nuclear genomes of local Malus sp. trees will reflect many ancestral groups. To test this hypothesis, we sequenced leaves from 94 Malus sp. trees throughout Boulder County using genotype-by-sequencing and compared their genetic variation to nuclear sequences of 20 Malus species from the NCBI GenBank repository using the software program Ohana and the R package pcAdapt.