This is a reversion of http://www.inaturalist.org/taxon_swaps/12212. While Ngā Tipu Aotearoa – New Zealand Plants places this species in Erythranthe, Calflora and GoBotany place it in Mimulus. The Plant List (our tie-breaker authority for plants) does not even include the name Erythranthe guttata, so I think there's a clear case to maintain placement in Mimulus.

Some useful links:

http://www.theplantlist.org/tpl1.1/record/kew-2506223
http://www.theplantlist.org/tpl1.1/search?q=Erythranthe+guttata (goes to an entirely different species)
https://gobotany.newenglandwild.org/species/mimulus/guttatus/
http://www.calflora.org/cgi-bin/species_query.cgi?where-calrecnum=5519
http://nzflora.landcareresearch.co.nz/default.aspx?selected=NameDetails&TabNum=0&NameId=E2E45D0B-4994-47EB-B0C9-42F2848EC950

See also this Google Group thread about this topic:
https://groups.google.com/d/topic/inaturalist/2ztt2BMqeCg/discussion

And for the record, while taxonomic revisions of Mimulus remain controversial, please remember that at iNat we do not base our taxonomy on primary taxonomic research unless we absolutely have to, and instead rely on the opinions of secondary taxonomic authorities. In this case, there are abundant opinions by secondary authorities, and that is the justification for making this change, not the strength of any underlying sequence data or what have you. For more about our policy of not following the primary literature, see http://www.inaturalist.org/pages/curator+guide#policies