Nellie, as a non-native English speaker I'm certainly the wrong person to decide if "spire" and "arch" can refer to the same thing. I wouldn't have thought so.
When I read the hand-written description by Garrard's I understood "spire" refers to what I called "stem" in my previous post and couldn't decide if the second word reads "bush" or "Arch" (with a capital A) or another English word I can't decipher.
In any case photos like the one I've posted suggest that 1) the base and 2) the stems/spires and 3) the arches/triangular elements with the central flowers are not connected to each other but hold in place by an inlying frame.