I went on a guided walk of the arboretum talking about Native California uses of plants. Pretty interesting. And in answer to the question what did they eat, well for many the staple was acorns. I've been curious to try them now for a while, but they seem fairly labor intensive to prepare.
Toyon berries - They're supposedly edible raw, but evidently branches were cut off the plant, the leaves stripped, and the berries roasted over an open fire. One of the guides said it was probably an aquired taste.
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Manzanita berries were mashed, then water added to make a refreshing drink. Several on the walk said it was good. And the hips from the native rose were used to make tea. (pic of rosehip, a little dry)
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Some of the most interesting uses of plants were not about food, but more on that after the jump.