What is an Italian countess called, like the "Barefoot" one in the 1954 Ava Gardner film?

Which word names both a type of eucalyptus tree and something kids chew? Which word names both a type of far-out 1960s music and the class of drugs that inspired it? Which word names both a type of fish and to sit on an elevated spot? Which type of hammer, with a rounded head, is used for shaping metal? Which type of lamp is powered up by a ballast? Which large snake may be reticulated? Which word names both a type of lizard and a computer screen? In health insurance, what does HMO stand for?