Shrine of Boundless Growth 
Artifact
At the beginning of your upkeep and whenever you cast a green spell, put a charge counter on this artifact.
, Sacrifice this artifact: Add 
for each charge counter on this artifact.
Legality
standardNOT LEGALpioneerNOT LEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL