http://www.starcitygames.com/magic/legacy/21524_The_Long_And_Winding_Road_Legacy_Elves.html
All the spells in that deck are green as are all the creatures. And yet the deck has two fetch lands - Misty Rainforests - which fetches islands and forests - and Verdant Catacombs - which fetches forests and swamps.
Some of the cards in the sideboard are blue and black I note. My guess: basic lands can be swapped out without needing to live in your sideboard?