I am putting on my grammar-geek-hat this morning and offering a post about the serial comma, a.k.a, the Oxford comma. Some say use it, others say lose it. Personally, I think a point not often made is that it’s often not necessary due to context.
First of all, I wouldn’t slow a sentence with an extra comma if the nouns in the list have no chance of being appositive. For example:
Mary, Ed and Lisa went to the pub.
There’s no way Ed and Lisa constitute Mary, so why use the comma?
Now, it’s a worthy distinction to put the comma in when it can clarify a relationship:
Mary’s concubines, Ed and Lisa, went to the pub.
Unless Mary has enslaved Ed and Lisa to her whims, a comma between ‘Ed’ and ‘and’ would be useful in specifying that ‘Ed and Lisa’ are not her concubines:
Mary’s concubines, Ed, and Lisa, went to the pub.
But what if we’ve already been reading a story about an ex-veterinarian named Mary who has gotten into undead animal husbandry? A pair of frisky ghoul-poodles have escaped and now they’re following around her friends hoping to get lucky. In that case, we probably know from the context that Ed and Lisa are not Mary’s bed slaves, but the marks of the rotted, curly-haired canine concubines…
…and the comma can be omitted.