Why is it called boston floor flange?

Because they use it in Boston?
Different names for different areas. Mark from Boston, (he should be answering this) calls a clean out tee a Dandy Clean Out.
Milo from California calls the lateral drainfrom the sink to the stack a Dirt Arm.
Go figure!! Cheers, Tom

Hi guys...

I've been in the plumbing trade in Boston since I was 15 and have never heard of a Boston floor flange. I'm not saying it doesn't exist... just never heard that reference before... ;)

If Ohoffman can give more details I may be able to figure out the reference.

Mark