Wow! I really learned something about commas while reading a blog thread. I am going to quote a post by Susan Uttendorfsky. I hope she doesn’t mind, but I am giving credit to her, and the reason I’m posting this is that there are writers who may stop by my blog and not know this, or not happen upon this thread at Linked In. I hope to post things beneficial to all of us here. So here goes. Please read carefully. This is interesting and important to know.
This is Susan’s post:
Descriptive Listing Commas
Mrs. Grade-School-English-Teacher didn't teach any of us a lot about using descriptive listing commas. One supposed trick is that if you can say a car is small AND blue, then it needs a comma. However, I've recently discovered that this trick doesn't work all the time.
For instance, a "red silk scarf" may indeed be red AND silk, but it doesn't need a comma. Why not? It's because there's a format for descriptions that reads "size - age - shape - color - origin - material". A list of descriptors in this order does not need commas: A large old rectangular black leather brief case. A large new narrow red velour blanket.
No commas. Seems strange, even to me, who wants desperately to punctuate those phrases with commas! But they're really not necessary.
The technical reasons are:
Cumulative adjective stacks, punctuated with no commas: Large red silk scarf.
Coordinate adjective stacks, punctuated with commas: Green, yellow, and red polka-dots.
Unit-modifier adjective stacks, mostly punctuated with hyphens, but sometimes not: long, stone-studded driveway.
Combination adjective stacks, containing a mixture of two or more of the previously listed categories: fast-moving, muddy cold water.
How many of you knew this, or is it more confusing than ever?