The guam-marr vial is made by using a marrentill on a guam vial or by using a guam on a marr vial. Producing the guam-marr vial from the empty vial yields a total of 168 Herblore experience. It is required to produce the waking sleep potion, which is required for the Lunar Diplomacy quest.
The next step is to use a ground tooth on the guam-marr vial.
