That's the ?-4 map, and it didn't give 10 LC, but rather 5 LC and randomly upto 2 LC per additional gold chest. The x2 isn't a multiplication to the guaranteed 5 LC, but a seperate reward.
The final map in each event rewarded the following LCs:
Hypericum: 6 LC - First event to award LC
Southern Cross: 6LC (random +2LC)
Canna: 6LC (random +2LC)
Calla: 6LC
Dipladenia: 6LC (random +2LC)
Gentian: 6LC (random +2LC)
Mirabilis: 6LC (random +2LC)
Monotropastrum: 6LC (random +2LC)
Robinia: 6LC (random +2LC)
Holly: 6LC (random +2LC)
Pine Tree: 6LC (random +2LC)
Lunaria (current): 6LC (random +2LC)