Acantha: In botany, a prickle; in zoology, a spine or prickly fin.
Acantha, in Greek mythology, was a beautiful nymph. Apollo fell in love with her. She resisted his advances. While pushing him away, she scratched his face. In anger, he turned her into a prickly plant.
These days, the word acantha shows up in the scientific names of spiky plants.
Acantha comes from the Greek words ἀκή (thorn) and ἄνθος (flower).