Does an "or" line on a power divide the entire card?

Does an "or" line on a power divide the entire card?

No. The "or" line only applies to the clauses immediately above and below the line, without extra whitespace.
For example, if you use Crops Wither and Fade, you always gain 2 fear and then you may choose whether you are replacing a City or a Town. On the other hand, on Tormenting Rotflies, you either choose everything above the "or" or everything below it.
To be explicit, the following cards have clauses that are not part of the "or" choice (separated by whitespace): Crops Wither and Fade; Growth Through Sacrifice; Sacrosanct Wilderness; Gift of the Primordial Deeps; Gift of Flowing Power; Call to Guard; Vanish Softly Away, Forgotten by All; Thickets Erupt with Every Touch of Breeze