Sources/Uses
Found in a variety of lichen species; Used as a pH indicator and in microscopy; Has been used to color beverages; [Merck Index] "The litmus mixture has the CAS number 1393-92-6 and contains 10 to 15 different dyes. . . . Acid-base indicators on litmus owe their properties to a 7-hydroxyphenoxazone chromophore." [Wikipedia]