The plant was initially identified as Mayaca sellowiana. The name in parenthesis is not a synonym or alternative name of some kind. If you look at the Tropica web site, they have "Pellia" in parenthesis under the newer and correct name Monosolenium tenerum. I guess that's to help people get up to speed, so to speak.
I believe that Mayaca sellowiana is a valid species, just not that one.