I have seen "Big Tooth Maple" given species rank and seen it listed as a subspecies of Sugar Maple. Since the later treatment is being used here I won't rock the boat. But there are two varities in Texas so I'm making a new thread "Acer saccharum ssp. grandidentatum var. sinuosum" I believe this is a smaller slowing growing variety Photo taken at San Antonio Botanical Garden 08-24-07
I'm in agreement with San Antonio Botanical Garden that Acer grandidentatum should be regarded as a distinct species ;-)