SP 2013, most recent updates on forms & workflows.
I'm wondering -- is there a way to tell which layout a form was submitted from? We have a worklfow we want to trigger on mobile submission, but not desktop submission. I seem to recall this existing previously but now I can't find it.
create a list field that will hold the layout type information.
place the list field on each layout, make sure controls are not linked across layouts.
configure different default values for above controls on different layouts.
based on which layout item was created from you will get populated different value into a list field. you can then decide whether to start a workflow or not.
other option might be to use forms metadata tags. they will, however, not tell which exact form layout was used but will tell from which device type and which OS item was sbmitted from