harrisia: genus of slender often treelike spiny cacti with solitary showy nocturnal white or pink flowers; Florida and Caribbean to South America
caryophylloid dicot genus: genus of relatively early dicotyledonous plants including mostly flowers
martensite: a solid solution of carbon in alpha-iron that is formed when steel is cooled so rapidly that the change from austenite to pearlite is suppressed; responsible for the hardness of quenched steel