Amethyst sea holly, (Eryngium amethystinum) or the amethyst eryngo,Italian eryngo is a clump-forming, perennial, tap-rooted herb. Its stem is 30 to 50 cm long and is light blue to purple in colour. The plant is native to the eastern Mediterranean and prefers dry places and soils that are rich in calcium.flowering on Mt Vettore, Umbria, Italy September, 2021