March of Burgeoning Life's target must have a mana value less than X. A creature with a mana value equal to X is not a legal target.
March of Burgeoning Life
The mana value of March of Burgeoning Life while it's on the stack is the value chosen for X plus 1, no matter how much mana you actually paid to cast it.
For example, say you wanted to choose a target with mana value 3. You need X to be at least 4. You could choose to cast March of Burgeoning Life by exiling two green cards from your hand and paying {G}, by exiling one green card and paying {2}{G}, or just by paying {4}{G}. If you had a reason to, you could even choose a greater value for X.
Magic: The Gathering · ™ & © Wizards of the Coast · Illus. Wylie Beckert
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