The “berry rule” is that 10% of white and yellow berries are edible; 50% of red berries are edible; 90% of blue, black, or purple berries are edible, and 99% of aggregated berries are edible. Aggregated fruits and berries are almost always edible (blackberry, raspberry, salmonberry, and thimbleberry). This is only a guideline, and unknown berries shouldn’t be eaten. It is simply not worth the risk, given the amount of calories they contain.
If you would like to know more about this subject, including a discussion on the quandary of whether or not to eat unidentified plants in a survival situation, head over to Dirt Time below.
(Photo from: Dirt Time)