How to tell the difference between blackberries and raspberries

To many of us, blackberry bushes and raspberry bushes can look very similar. How can you tell the difference between a black raspberry and a blackberry?

Simple. Pick them, and look in the middle. A raspberry (even black raspberries) will have a hollow in the middle, because the core stays on the plant. A blackberry, when picked, will have a solid core that comes with the berry.

I can’t really document the blackberry side because they’re a month out of ripeness yet, but our raspberries have just started giving abundantly so pictures of those are easy.

Also, this section of the Wikipedia article on raspberries illustrates the difference pretty well.