The text on Omnath, Locus of Mana says, "You don't lose unspent green mana as steps and phases end."
The rulings info on Gatherer says, "You can keep green mana in your mana pool indefinitely while Omnath is on the battlefield. That means if you add a green mana to your mana pool during one step or phase, you can spend it during a later step or phase, or even a later turn."
Will Omnath, Locus of Mana keep your green mana available from turn to turn? Even though the text only mentions steps and phases? Does the text on the card imply that you can keep green mana even after your ending phase ends?
Yes. Every turn of a Magic game is divided into phases (C.R. 500.1), so if you control Omnath, you don't lose unspent green mana as turns end (including as the ending phase of a turn ends).
If you control Omnath, C.R. 500.4 simply doesn't apply to you with respect to green mana (C.R. 101.1, 109.5).
The text on Omnath, Locus of Mana says, "You don't lose unspent green mana as steps and phases end."
The rulings info on Gatherer says, "You can keep green mana in your mana pool indefinitely while Omnath is on the battlefield. That means if you add a green mana to your mana pool during one step or phase, you can spend it during a later step or phase, or even a later turn."
Will Omnath, Locus of Mana keep your green mana available from turn to turn? Even though the text only mentions steps and phases? Does the text on the card imply that you can keep green mana even after your ending phase ends?
The rules say you lose unspent mana when a step or phase ends. Not "when a step, phase, or turn ends".
You normally loses unspent mana when your turn ends because the Cleanup Step and the Ending Phase ended, not because the turn itself ended. Omnath makes so that even the very last step/phase in a turn doesn't cause you to lose green mana, and so the mana remains for the following turn, and the one after it, until spent.
The rulings info on Gatherer says, "You can keep green mana in your mana pool indefinitely while Omnath is on the battlefield. That means if you add a green mana to your mana pool during one step or phase, you can spend it during a later step or phase, or even a later turn."
Will Omnath, Locus of Mana keep your green mana available from turn to turn? Even though the text only mentions steps and phases? Does the text on the card imply that you can keep green mana even after your ending phase ends?
If you control Omnath, C.R. 500.4 simply doesn't apply to you with respect to green mana (C.R. 101.1, 109.5).
The rules say you lose unspent mana when a step or phase ends. Not "when a step, phase, or turn ends".
You normally loses unspent mana when your turn ends because the Cleanup Step and the Ending Phase ended, not because the turn itself ended. Omnath makes so that even the very last step/phase in a turn doesn't cause you to lose green mana, and so the mana remains for the following turn, and the one after it, until spent.
RULES OF MAGIC :
http://magic.wizards.com/en/game-info/gameplay/rules-and-formats/rules