The city of Los Angeles comprises nearly 500 square miles and supports nearly four million people who reside on lands that were once composed of a diverse mosaic of wetland and upland plant community associations. On top of these historic vegetation layers are socioeconomic legacies of a redlining grading system for the city established by the Federal Housing Administration's Home Owners Loan Corporation (HOLC). Throughout neighborhoods in public parkways, the spaces between property bounds and the road, reside an often overlooked spontaneous and self-propagating community of native and introduced taxa. With an interest in documenting this flora at a time of rapid environmental and socioeconomic change in the city, I performed a series of floristic checklists for nearly 400 blocks comprising nearly 50 total miles at sixteen neighborhoods throughout the city between the end of January and middle of March 2021. Transects were walked within specific neighborhood communities chosen to represent all four HOLC codes and a combination of historic wetland and upland vegetative communities. Across all transects and sites, I found a total of 168 spontaneous self-propagating plant taxa, and a significant effect of historical plant community (upland, wetland) on plant species richness and phylogenetic diversity but not HOLC code. I also present and discuss patterns of community similarity and turnover between sites. This dataset of plant species presence by block, and the list of transect locations, is publicly available via dataDryad so that it may serve as a point of reference for future studies of urban ethnobiology.

Data was collected by performing a series of walking transect checklists to identify and list each species that occurs on each block surveyed. Data consists of a matrix of each transect and whether each taxon was present (1) or absent (0).