Why don’t we use a comma with coordinate items containing a coordinating conjunction?

Question

In a book I had read about punctuation, it wasn’t clear about coordinate items in which one of the items contains a coordinating conjunction.

This was the example:

“The resort offers elegantly appointed rooms, casitas, and villas and four swimming pools, along with other existing amenities.”

I’m guessing the reason there’s not a comma after villas is that the four swimming pools are included with the villas. If it isn’t the reason, why don’t we need a comma after villas?

Answer 1

It's because there are two lists. The first list is "things that are elegantly appointed"; the modifier "elegantly appointed" fronts the list and applies to everything in it. "Appointed" in this sense is about interior decoration and doesn't apply to swimming pools.

You could imagine building this structure up from something simple:

• Bill rides horses and bicycles. (There are only two items in this list so no comma is needed.)
• Bill rides horses, elephants, zebras, and bicycles. (This is still just a list of things he rides.)
• Bill rides [wild horses, elephants, and zebras] and bicycles. (There is a "big list" of two items and they are both things he rides. The first item is itself a list of wild animals. It would be a mistake to leave out the "and" before zebras because bicycles are not wild.)

Now, this zebras-and-bicycles sentence isn't very comfortable, and it might be smart to reword it. I think I might feel the same way about the example sentence for the resort. There's a danger that, reading my sentence, the reader thinks that the modifier "wild" only applies to the "horses," and the second item in the list is just "elephants." Something like this might be clearer and flow better: "After its redesign, the resort now offers elegantly appointed rooms, casitas, and villas, as well as four new swimming pools, along with other existing amenities."