Hemidictyum

Hemidictyum is a genus of ferns with a single species, Hemidictyum marginatum, commonly known as the marginated half net fern.[3] In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), it is the only genus in the family Hemidictyaceae.[4] Alternatively, the family, along with Aspleniaceae sensu stricto, may be placed in a much more broadly defined family Aspleniaceae as the subfamily Asplenioideae.[5]

Hemidictyum
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Class:	Polypodiopsida
Order:	Polypodiales
Suborder:	Aspleniineae
Family:	Hemidictyaceae Christenh. & H.Schneid.
Genus:	Hemidictyum C.Presl[1]
Species:	H. marginatum
Binomial name
Hemidictyum marginatum (L.) C.Presl[2]
Synonyms[2]
Allantodia marginata Racib. Asplenium limbatum Willd. Asplenium marginatum L. Asplenium mikanii C.Presl Athyrium marginatum Milde Diplazium giganteum Karst. Diplazium limbatum (Willd.) Proctor Diplazium marginatum Diels Hemidictyum limbatum (Willd.) C.Presl Hemidictyum peruvianum C.Presl

Taxonomy

The name Hemidictyum was derived from the terms hemi (half) and diktyon (net), from the veins being netted only half-way across the pinnules.[6]

Phylogenetic relationships

Hemidictyaceae is considered to be a sister family to Aspleniaceae s.l., believed to have diverged during the Cretaceous period.[7][8] The following cladogram for the suborder Aspleniineae (as eupolypods II), based on Lehtonen (2011),[9] and Rothfels & al. (2012),[10] shows a likely phylogenetic relationship between the Hemidictyaceae and the other families of the clade.

Aspleniineae (eupolypods II)	Cystopteridaceae         Rhachidosoraceae       Diplaziopsidaceae       Aspleniaceae     Hemidictyaceae             Thelypteridaceae       Woodsiaceae         Onocleaceae     Blechnaceae       Athyriaceae

Species

There is currently only one accepted Hemidictyum species, Hemidictyum marginatum.[1]

Distribution

Hemidictyum is a native neotropical fern, found in Mexico, the Caribbean, Costa Rica, Guatemala, Honduras, Nicaragua, Panama, French Guiana, Suriname, Brazil, Venezuela, Puerto Rico, Bolivia, Colombia, Ecuador, and Peru.[3][11]

References

1. "Hemidictyum C.Presl". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 2019-11-28.
2. "Hemidictyum marginatum (L.) C.Presl". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 2019-11-28.
3. "Hemidictyum marginatum". Natural Resources Conservation Service PLANTS Database. USDA. Retrieved 4 Feb 2012.
4. PPG 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.
5. Christenhusz, Maarten J.M. & Chase, Mark W. (2014). "Trends and concepts in fern classification". Annals of Botany. 113 (9): 571–594. doi:10.1093/aob/mct299. PMC 3936591. PMID 24532607.
6. The Fern Manual, being a description of all the best stove, greenhouse and hardy ferns by contributors to the Journal of Horticulture p.69, London, 1863
7. Maarten J. M. Christenhusz; Xian-Chun Zhang; Harald Schneider (2011). "A linear sequence of extant families and genera of lycophytes and ferns" (PDF). Phytotaxa. 19: 7–54.
8. Maarten J. M. Christenhusz; Harald Schneider (2011). "Corrections to Phytotaxa 19: Linear sequence of lycophytes and ferns" (PDF). Phytotaxa. 28: 50–52.
9. Samuli Lehtonen (2011). "Towards Resolving the Complete Fern Tree of Life" (PDF). PLoS ONE. 6 (10): e24851. doi:10.1371/journal.pone.0024851. PMC 3192703. PMID 22022365.
10. Carl J. Rothfels; Anders Larsson; Li-Yaung Kuo; Petra Korall; Wen- Liang Chiou; Kathleen M. Pryer (2012). "Overcoming Deep Roots, Fast Rates, and Short Internodes to Resolve the Ancient Rapid Radiation of Eupolypod II Ferns". Systematic Biology. 61 (1): 70. doi:10.1093/sysbio/sys001. PMID 22223449.
11. "Hemidictyum marginatum". Germplasm Resources Information Network (GRIN). Agricultural Research Service (ARS), United States Department of Agriculture (USDA). Retrieved 12 January 2018.