Cydista and Pachystegia, are related to what?
Pachystegia Pachystegia is a genus of shrubs in the daisy family described as a genus in 1925.
Adiantaceae Adiantaceae (as construed here, "sensu stricto", not a synonym of Pteridaceae) is a family of ferns in the order Pteridales. This includes the family formerly known as the "Vittariaceae." Recent genetic analyses based on chloroplast genes demonstrate that the vittarioid ferns cladistically nest within the genus "Adiantum", making that genus paraphyletic.