Anne, the maker of this cake stand has been a mystery for a long time. There is a celery vase in the same pattern (as well as a variant) too, that are also marked with the same RD. The pattern is known as FINE CUT RINGS. We have 1928 Pottery Gazette ads that show the celery vase (as well as the variant). Various makers names have been thrown into the arena: Leerdam and Rindskopf to mention just two. But so far, despite a lot of searching, the maker hasn't yet been found. Hopefully someone else will be able to attribute it.
Glen