When it comes to green many artists like to mix their own, but there is always room for Sap Green.
Sap green is a lake pigment and was originally made from the juice of unripe berries from the buckthorn, (Rhamnus) plant. In medieval times the extracted colour was reduced to a heavy syrup and sold in pig bladders rather than a dry pigment.
Winsor Newton
Sap Green is a favorite on my palette and here are some examples of tube and mixed greens to make the point that there are endless choices.
Own Your Encore 