Holly-leaved cherries (Prunus ilicifolia), seen here in the process of ripening, are a wild grown food that can be foraged in the local mountains.
“Prunus ilicifolia is the most common wild cherry in coastal California south of San Francisco Bay, and it was used as food by every group in whose territory it occurs.”
—Jan Timbrook Chumash Ethnobotany: Plant Knowledge Among the Chumash People of Southern California
Holly-leaved cherries, called ‘akhtayukhash in Barbareno Chumash, are fruiting right now. The fruit, which grows as a thin layer of flesh covering a hard marbled-sized seed pod, is edible right off the plant. The pulp is not much thicker than the skin and offers little more than a taste, but it is juicy and sweet tasting.
Though the pulp is edible, the kernel within the fruit pit was the most valued part of the plant for the Chumash Indians. The seed pods were cracked and the kernels collected, which could then when dried be stored for as long as necessary until they were needed.
The kernels, however, contain hydrocyanic acid and are poisonous. Before eating them they must be properly prepared to remove the poison, as well as their bitter taste. The preparation process involves leaching the poison from the kernels using fresh water.
After the kernels were leached of poison, they were cooked for several hours by boiling until they became soft, then mashed, rolled into balls and coated in pinole flour made from juniper or grass seeds. “The Chumash consultants,” Timbrook notes, “all agreed that it was a good-tasting and prized food.” The small cakes were eaten with roasted meat and were also a featured food in ceremonial events.
A cherry pit without the skin showing some of the yellow fruit pulp still clinging to the seed pod.
Jack Elliott's Santa Barbara Adventure 
Timely post. We recently planted three Catalina Cherry saplings in our back yard. No fruit yet but one of these days.
The preparation of the cherry meal sounds very similar to the process used to leach the tannins out of acorns. Soak, boil, mash, then soak and boil some more and on and on through a couple of rounds before the meal was ready to be formed into cakes and baked.
Interesting stuff. I always wonder how many rounds of trial and error it took to figure out something could be edible if only its prepared right. Think they drew straws to see who would be the trial taster?
There is a larger fruiting variety that grows on the islands and, yeah, the prep process is pretty much the same as acorns.
Maybe the punishment for wayward Indians was to make them try out new foods and see if they lived or got the runs, heheh.
I wonder when, what date or time frame in history, all the food they were known to have eaten was known to be safe. In other words, what period of time was there an active investigatory stage where they were actually experimenting and eating new foods that they were not sure were safe and nutritious to eat.