If a nonbasic land has an ability that causes it to enter the battlefield tapped, it will lose that ability before it applies. The same is also true of any other abilities that modify how a land enters the battlefield or apply "as" a land enters the battlefield, such as the first ability of Cavern of Souls.
Celestial Dawn
Mana produced by spells you control and nonland permanents you control isn't affected by Celestial Dawn. Llanowar Elves will produce {G}, for example. However, any colored mana may be spent only on the colorless part of costs.
Land cards you own that aren't on the battlefield aren't changed to Plains.
Magic: The Gathering · ™ & © Wizards of the Coast · Illus. Liz Danforth
Card data via Scryfall. Rarix is fan-made; not endorsed by the rights holders.
