Vittarioideae is a subfamily of the fern family Pteridaceae, in the order Polypodiales.[1][2] The subfamily includes the previous families Adiantaceae (adiantoids or maidenhair ferns) and Vittariaceae (vittarioids or shoestring ferns).[3]
Description
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 ferns historically considered as Adiantum include both petrophilic and terrestrial plants. The vittarioid ferns are primarily epiphytic in tropical regions and all have simple leaves with sori that follow the veins and lack true indusia; the sori are most often marginal with a false indusium formed from the reflexed leaf margin. The family also includes a species, Vittaria appalachiana, that is highly unusual in that the sporophyte stage of the life cycle is absent. This species consists solely of photosyntheticgametophytes that reproduce asexually.[citation needed]
The first suprageneric classification based on Vittaria was made by Carl Borivoj Presl in 1836, who erected the tribeVittariaceae to contain the genera Vittaria and Prosaptia, the latter now included in the grammitid ferns. He invented the new genus Haplopteris to accommodate another group of simple-leaved ferns separated from Pteris, but placed it in tribe Adiantaceae instead, due to the location of its sori just behind the leaf margin.[6]
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.[9]
The first well-sampled molecular phylogeneticstudy of the vittarioids was based on the chloroplastgenerbcL. In this study, it was found that the type species of Monogramma is embedded in Haplopteris; the segregation of Vaginularia from Monogramma was also supported, as members of Vaginularia formed a clade sister to Rheopteris and distant from Monogrammasensu stricto.[10] A later molecular phylogeny, published in 2016, established the genus Antrophyopsis (formerly a subgenus of Antrophyum) for three species placed in Scoliosorus but more distant from the type of that genus than Antrophyum. This treatment also sank Anetium into Polytaenium and Monogramma into Haplopteris.[11] Since the name Monogramma has taxonomic priority over Haplopteris, a proposal to reject Monogramma in favor of Haplopteris has been put forth to conserve the name and comparatively stable circumscription of Haplopteris.[12]
Genera
The following genera are recognized in the Pteridophyte Phylogeny Group classification of 2016 (PPG I):[1]
^ abcPPG I (2016). "A community-derived classification for extant lycophytes and ferns". Journal of Systematics and Evolution. 54 (6): 563–603. doi:10.1111/jse.12229.
^ abSchuettpelz et al. (2007)Archived 2008-08-20 at the Wayback Machine Eric Schuettpelz, Harald Schneider, Layne Huiet, Michael D. Windham, Kathleen M. Pryer: "A molecular phylogeny of the fern family Pteridaceae: Assessing overall relationships and the affinities of previously unsampled genera." Molecular Phylogenetics and Evolution44 (2007) 1172–1185
^Ching, Ren-Chang (1940). "On natural classification of the family Polypodiaceae". Sunyatsenia. 5: 232.
^Bradley Ruhfel, Stuart Lindsay, and Charles C. Davis. 2008. "Phylogenetic Placement of Rheopteris and the Polyphyly of Monogramma (Pteridaceae s.l.): Evidence from rbcL Sequence Data". Systematic Botany33(1):37-43, doi:10.1600/036364408783887410