Cayenne/Ground Red Pepper: The rusty red powder that you find in spice jars. Spicy!
Crushed Red Pepper: The pepper flakes you find in jars at Italian restaurants. You can also buy them at Penzey's -- theirs are pretty good!
"In all our woods there is not a tree so hard to kill as the buckeye. The deepest girdling does not deaden it, and even after it is cut down and worked up into the side of a cabin it will send out young branches, denoting to all the world that Buckeyes are not easily conquered, and could with difficulty be destroyed." - Daniel Drake, 1833