Althea, Preternatural Grower

Whenever a land enters the battlefield under
your control, you may pay {1}. If you do, put a
Seed token onto the battlefield that's tapped.
(It's an artifact with "{t}, Sacrifice this artifact: add {2} to you mana pool.")
Whenever you cast a spell with converted mana
cost 6 or greater, you may search your library
for a basic land card. If you do, put it onto the battlefield, then shuffle your library.