| Plexico |
This question has raised some debate with my gaming group. As far a scorching ray goes, since all the rays require a separate attack roll, we agreed that the + fire damage applies to each ray. Produce flame similarly would get the bonus every time it dealt damage, as each attack occurs on a separate attack roll and round.
As far as other spells and effects go, some are trickier than others.
The spell flame arrow seems to indicate that + fire damage would work on every arrow affected by it. If you are in Form of the Dragon, the breath weapon would benefit from the + fire damage.
I had wanted the Claws ability from the draconic bloodline of the sorcerer to count, but supernatural abilities are explicitly not spells. Darn.
If you multi-classed into paladin the Divine bond class feature is spell-like and I propose that making a weapon flaming from that ability gets the bonus as well.