It's downright fascinating to me how we can happen across info we've been looking for. I have a plant in my yard that was given to me several years ago by the late Millie Clark (the same lady who gave me the ginger lily). I could tell the bloom looked a bit like a hibiscus bloom, so I thought it might be a mallow of some sort. (The mallow family includes plants such as rose of Sharon, okra, cotton, and hollyhock.)
Anyway, someone had posted a picture of a littleleaf sumac on a forum I frequent. In tracking down the littleleaf sumac id, I found a picture of a plant like mine. Now I know I have malvaviscus arboreus in my yard.
Here are some pics of my Texas mallow.