Wall of Fire

[Delenot]

Does a Wall of Fire have to be anchored, or can it be cast in an open space?

For example: The description says the wall is immobile. Could cast in the air and hang there unattached burning away?

[Pizza Lord]

I don't see anything preventing it from being unanchored. Unlike the rules for Conjuration effects which specify that a created object not be floating in the air, I don't see a similar restriction for Evocation spells.

Also, looking at the sidebar which discusses casting wall of fire upon the deck of a ship and then it staying in that position on the vessel, whereas not casting it on the deck of the ship means it doesn't move with the ship, seems to imply that you can.

PathfinderSRD Wall of fire wrote:

A wall of fire cast on the deck of a ship moves with the ship and can start on-board fires. Otherwise, the wall does not move with the ship, and does not start on-board fires.