The Serial Comma
In the following sentence, the red comma is called the serial comma.
Temperature, moisture, and pH were measured.
The serial comma is the one that precedes the and (or some other conjunction) in a series of three or more items.
Although newspapers, popular magazines, and even some scientific journals do not use the serial comma, most grammar authorities recommend that it be used to avoid confusion. These authorities include Fowler, Strunk and White, Garner, The Council of Science Editors, and The Chicago Manual of Style.
I always use the serial comma because it sometimes reduces confusion (see the end of this entry for an example) and only rarely increases confusion. I also use the serial comma because some readers (usually the better ones, i.e., those who have read Fowler, Strunk and White, Garner, etc.) expect it.
It seems that the serial comma is controversial. You can find a lot about it on-line, and if you do waste your time looking as I did, you might conclude that there is no consensus about its use. But not all votes are equal. Your vote is not equal to Fowler's, who was British, or to Strunk and White's, who were American. I bring up nationality here to prevent the possibility that we might use punctuation as cause to invade another country.
If the journal where the paper will be published does not use the serial comma, the journal's copy editor will simply remove it. You can perhaps reinsert the serial commas in the proofs but the technical editor will probably ignore your insertions. And you will probably have bigger concerns, as in Why have all my sentences been changed to passive voice? What genus thinks that It was hypothesized that is better than We hypothesized that? or Where is Table 3? They left out Table 3! At that point, a few commas here or there are unlikely to get your attention.
As with all other writing decisions, consider whether the serial comma increases or decreases sentence clarity before you insert or delete it. In many cases, it will probably do neither. And then consider Fowler, Strunk and White and Garner. But did Strunk and White write a book with Garner. No? Then, it should be Fowler, Strunk and White, and Garner. So, insert the damn comma and stop bothering me.