I recognize that my initial example may have been ill-chosen since the Calflora range tool stops at the border, despite having data beyond it. However, the actual known data does support my point.
In the Calflora database, six percent of the Xylococcus Bicolor observations extend beyond the border. Most of these are dated, and the plants may no longer exist. Filtering for observations that are more recent than 1990, the number falls closer to two percent beyond the border.
Local researchers are aware of this issue, and I've come across it in various research papers on Xylococcus Bicolor.
If you're truly curious the author of that thesis expanded his work into the book "Kumeyaay Ethnobotany: Shared Heritage of the Californias" that looks more closely at these issues.
In the Calflora database, six percent of the Xylococcus Bicolor observations extend beyond the border. Most of these are dated, and the plants may no longer exist. Filtering for observations that are more recent than 1990, the number falls closer to two percent beyond the border.
Local researchers are aware of this issue, and I've come across it in various research papers on Xylococcus Bicolor.
This thesis on the region's ethnobotany frequently cites the border as a cutoff or dividing line in research. https://www.sandiegocounty.gov/content/dam/sdc/pds/ceqa/JVR/...
If you're truly curious the author of that thesis expanded his work into the book "Kumeyaay Ethnobotany: Shared Heritage of the Californias" that looks more closely at these issues.