Devotion change due to Songs of the Dryad?
Hi,
Thanks for your question. The Song only affects the color of the card (by making it colorless), types that it has (and subtypes that it has), and any abilities it has (and gains the ability to tap for one green mana since it's a Forest). It won't affect anything else, like the mana cost of the card. Even if it's enchanted by the Song, the Tusker's mana cost is not affected, so it will still provide two to devotion to green.
205.1a Some effects set an object’s card type. In such cases, the new card type(s) replaces any existing card types. Counters, effects, and damage marked on the object remain with it, even if they are meaningless to the new card type. Similarly, when an effect sets one or more of an object’s subtypes, the new subtype(s) replaces any existing subtypes from the appropriate set (creature types, land types, artifact types, enchantment types, planeswalker types, or spell types). If an object’s card type is removed, the subtypes correlated with that card type will remain if they are also the subtypes of a card type the object currently has; otherwise, they are also removed for the entire time the object’s card type is removed. Removing an object’s subtype doesn’t affect its card types at all.
Nathan Long
Magic Rules NetRep