Photo: Diane Edwardson, July 7, 2014. Many of the native Blue Elderberry Trees (Sambucus nigra) are dying out in the neighborhood. However, this one on the top of Red Car Canyon on Corralitas Drive is one of the few doing quite well. (Click on photo to enlarge.)
According to UC Berkeley, Blue Elderberries in California are not "Mexican Elderberries:" The Jepson Flora Project
According to Cal Flora & California Poison Control, Blue Elderberry Trees are majorly toxic, however the ripe fruit is not. Eat at your own risk.
Disclaimer: The Corralitas Red Car Property Blog prefers to quote reliable sources, such as CalFlora and California Poison Control on the issue of toxicity. We often get email suggesting some plants are edible. If you are eating your way through the Red Car Property, we DO NOT recommend you eat any plant you find in the Red Car Property neighborhood without first doing your own research.