Domain abilities count the number of basic land types among lands you control, not how many lands you control or how many of any type.
2022-09-09
The basic land types are Plains, Island, Swamp, Mountain, and Forest. Land types other than basic land types (such as Desert) don’t contribute to domain abilities.
Domain — Territorial Maro's power and toughness are each equal to twice the number of basic land types among lands you control.
