Some years ago, I bought a cactus with a strawflower glued to its head (sorry, couldn't resist
Getting the strawflower off the cactus is sometimes challenging. Sometimes it takes patience until the flower is "pushed" off the body of the cactus (cactus bodies are very waxy so its only a matter of time before the glue comes unglued). If the only way to remove the green flower is to rip off some hide, don't do it. Sometimes (luckily) the flowers are only attached to the spines so can be cut off (don't worry about cutting spines - it doesn't hurt. Honest!).
Anyway, it seemed to me that my strawflower was forming seeds! So I planted them and was rewarded with a bunch of really boring strawflowers. Apparently, the flowers are also dyed.