Wikipedia
Vittarioideae is a subfamily of the Pteridaceae family of ferns, in the order Polypodiales, class Polypodiopsida. This subfamily includes the previous families Adiantaceae (adiantoids or maidenhair ferns) and Vittariaceae (vittarioids or shoestring ferns).
The subfamily includes two distinct groups of ferns: the adiantoids, consisting of the single genus Adiantum, and the vittarioids, several genera, including Vittaria, which typically have highly reduced leaves, usually entire, and an epiphytic habit.
The first suprageneric classification based on Vittaria was made by Carl Borivoj Presl in 1836, who erected the tribe Vittariaceae to contain the genera Vittaria and Prosaptia, the latter now included in the grammitid ferns.
In his 1911 treatment of the tribe, Ralph Benedict recognized seven of the eleven vittarioid genera of modern treatments: he described Radiovittaria as a subgenus of Vittaria, subsumed Scoliosorus within Polytaenium as doubtfully worthy of subgeneric rank, while Rheopteris had not yet been discovered. Haplopteris he explicitly synonymized with Vittaria in 1914.
Carl Christensen used the name "Vittarioideae" in Verdoorn's Manual of Pteridology in 1938, but did not include a description, leaving it nomenclaturally invalid. Ren-Chang Ching raised Vittariaceae to the rank of a family in 1940.
The following diagram shows a likely phylogenetic relationship between the Vittarioideae and other subfamilies of the Pteridaceae.
The first well-sampled molecular phylogenetic study of the vittarioids was based on the chloroplast gene rbcL. In this study, it was found that the type species of Monogramma is embedded in Haplopteris. Because Monogramma is the older name, unless Haplopteris is split, all of the species of Haplopteris will eventually be transferred to Monogramma.