Rhachidosorus

Rhachidosorus
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Division:	Polypodiophyta
Class:	Polypodiopsida
Order:	Polypodiales
Suborder:	Aspleniineae
Family:	Rhachidosoraceae X.C.Zhang
Genus:	Rhachidosorus Ching
Species
See text
Synonyms[1]
Rhachidosoroideae M.L.Wang & Y.T.Hsieh

Rhachidosorus is a genus of ferns in the order Polypodiales.^[2] It is the only genus in the family Rhachidosoraceae in the Pteridophyte Phylogeny Group classification of 2016 (PPG I).^[3] Alternatively, the genus may be placed in the subfamily Rhachidosoroideae of a more broadly defined family Aspleniaceae,^[1] the family placement used in Plants of the World Online as of November 2019^[update].^[4]

Species

The genus was described by Ren Chang Ching in 1964, with about 7 species in eastern and southeastern Asia, including Japan, the Philippines, and Sumatra.^[5] As of November 2019^[update], Plants of the World Online accepted the following species:^[4]

• Rhachidosorus blotianus Ching – China, Vietnam
• Rhachidosorus chrysocarpus (Alderw.) Ching
• Rhachidosorus consimilis Ching – China (Guizhou, Sichuan, Yunnan)
• Rhachidosorus mesosorus (Makino) Ching – China, Japan, South Korea
• Rhachidosorus pulcher (Tagawa) Ching – Taiwan, Yunnan
• Rhachidosorus siamensis S.Linds.
• Rhachidosorus stramineus (Copel.) Ching
• Rhachidosorus truncatus Ching – China (Guangxi, Guizhou, Yunnan)

Phylogenic relationships

The following diagram for the eupolypods II, based on Lehtonen, 2011,^[6] and Rothfels & al., 2012,^[7] shows a likely phylogenic relationship between the Rhachidosoraceae and the other families of the eupolypods II clade.

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

References

1. 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.
2. Alan R. Smith; Kathleen M. Pryer; Eric Schuettpelz; Petra Korall; Harald Schneider & Paul G. Wolf (2006). "A classification for extant ferns" (PDF). Taxon. 55 (3): 705–731. doi:10.2307/25065646. JSTOR 25065646.
3. 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. S2CID 39980610.
4. "Rhachidosorus Ching". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 2019-11-27.
5. 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. doi:10.11646/phytotaxa.19.1.2.
6. Samuli Lehtonen (2011). "Towards Resolving the Complete Fern Tree of Life" (PDF). PLOS ONE. 6 (10): e24851. Bibcode:2011PLoSO...624851L. doi:10.1371/journal.pone.0024851. PMC 3192703. PMID 22022365.
7. 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): 490–509. doi:10.1093/sysbio/sys001. PMID 22223449.