| Hymenophyllum | 
  |   | 
  | A plate featuring Hymenophyllum species from The Ferns of Great Britain and Ireland | 
       | Scientific classification   | 
  | Kingdom: | Plantae | 
  | Clade: | Tracheophytes | 
  | Division: | Polypodiophyta | 
  | Class: | Polypodiopsida | 
  | Order: | Hymenophyllales | 
  | Family: | Hymenophyllaceae | 
  | Subfamily: | Burnett
 | 
  | Genus: | Sm.
 | 
                                                                                                             | Type species | 
  | Hymenophyllum tunbrigense 
 (L.) Sm. | 
                        | Synonyms[1] | 
  |   Amphipterum C.Presl 1849-51 ex (Copeland 1937) Copeland 1938 Apteropteris (Copeland 1937) Copeland 1938 Buesia (Morton 1932) Copeland 1938 Cardiomanes C.Presl 1843 Craspedoneuron van den Bosch 1861 Craspedophyllum (Presl 1843) Copeland 1938 Dermatophlebium C.Presl 1849-51 Diploophyllum Bosch Hemicyatheon (Domin 1913) Copeland 1938 Hymenoglossum K.B.Presl, 1843 Leptocionium K.B.Presl, 1843 Leucomanes Presl 1851 Mecodium Presl ex (Copeland 1937) Copeland 1938 Meringium K.B.Presl, 1843 Microtrichomanes (Mettenius 1864 ex Prantl 1875) Copeland 1938 Myriodon (Copeland 1937) Copeland 1938 Myrmecostylum K.B.Presl, 1843 Pachyloma van den Bosch 1861 Pleuromanes (Presl 1851) Presl 1849-51 Pseudomecodium (Iwatsuki 1984) Satou 1997 Ptychomanes Hedwig 1800 Ptychophyllum K.B.Presl, 1843 Rosenstockia Copeland 1947 Serpyllopsis van den Bosch 1861 Sphaerocionium K.B.Presl, 1843  Tetralasma Philippi 1860 
 | 
  
 Hymenophyllum is a genus of ferns in the family Hymenophyllaceae. Its name means "membranous leaf", referring to the very thin translucent tissue of the fronds, which gives rise to the common name filmy fern for this and other thin-leaved ferns. The leaves are generally only one cell thick and lack stomata, making them vulnerable to desiccation.  Consequently, they are found only in very humid areas, such as in moist forests and among sheltered rocks. They are small and easy to overlook. 
  Species
 As of October 2022, World Ferns accepted the following extant species:[2] 
    | Phylogeny of Hymenophyllum[3][4] | Unassigned species: | 
  |      |  |      |  |      | (Myrmecostylum) |      |  |      |  | H. scabrum A.Rich.  |   |  |   |  |      |  | H. sanguinolentum (G.Forst.) Sw. (Piripiri)  |   |  |   |  | H. villosum Colenso  |   |  |  |   |  |  |   |  |   |  |      |  | H. paniense Ebihara & K.Iwats.  |   |  |   |  |      |  | H. plicatum Kaulf.  |   |  |   |  |      |  | H. seselifolium C.Presl  |   |  |   |  | H. tortuosum Hook. & Grev.  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |   |  |      |  |      | (Pleuromanes) |      |  | H. pallidum (Blume) Ebihara & K.Iwats.  |   |  |   |  |  |   |  |  |   |  |  |   |  |   |  |      |  |      | (Hymenoglossum) |      |  | H. asplenioides (Sw.) Sw.  |   |  |   |  |  |   |  |  |   |  |  |   |  |   |  |      |  |      |  |      | (Diplophyllum) | H. dilatatum (G.Forst.) Sw.  |   |  |   | (Cardiomanes) | H. nephrophyllum Ebihara & K.Iwats. (Kidney fern)  |   |  |  |   |  |   |  |      | (Fuciformia) |      |  | H. fuciforme Sw.  |   |  |   |  | H. pulcherrimum Colenso  |   |  |  |   |  |  |   |  |  |   |  |   |  |      |  |      | (Globosa) |      |  |  |   |  |   |  |      |  | H. caudiculatum Mart. (Pallante chilote)  |   |  |   |  |      |  | H. imbricatum Blume  |   |  |   |  |      |  |      |  | H. pluviatile Perrie & Brownsey  |   |  |   |  |      |  | H. australe Willd. (Austral filmy ferm)  |   |  |   |  | H. fucoides (Sw.) Sw.  |   |  |  |   |  |  |   |  |   |  |      |  | H. flexuosum A.Cunn.  |   |  |   |  |      |  | H. gracilescens Domin  |   |  |   |  |      |  | H. javanicum Spreng.  |   |  |   |  | H. riukiuense Christ  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |   |  |      |  |      | (Sphaerocionium) |      | section |      |  | H. subobtusum Rosenst.  |   |  |   |  |      |  | H. frankliniae Colenso  |   |  |   |  |      |  |      |  | H. pilosissimum C.Chr.  |   |  |   |  |      |  | H. lanceolatum Hook. & Arn.  |   |  |   |  | H. obtusum Hook. & Arn.  |   |  |  |   |  |  |   |  |   |  |      |  | H. lyallii Hook.fil.  |   |  |   |  |      |  |      |  | H. neocaledonicum (C.Chr.) Rouhan & C.Del Rio  |   |  |   |  |      |  | H. braithwaitei Ebihara & K.Iwats.  |   |  |   |  | H. tomentosum Kunze  |   |  |  |   |  |  |   |  |   |  |      |  | H. digitatum (Sw.) Fosberg  |   |  |   |  |      |  | H. nitidulum (Bosch) Ebihara & K.Iwats.  |   |  |   |  | H. palmatifidum (Müll.Berol.) Ebihara & K.Iwats.  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   | Microtrichomanes |   | section |      |  | H. malingii (Hook.) Mett.  |   |  |   |  |      |  | H. hygrometricum (Poir.) Desv.  |   |  |   |  |      |  |      |  | H. capillare Desv.  |   |  |   |  | H. ferrugineum Colla  |   |  |  |   |  |   |  |      |  | H. poolii Baker  |   |  |   |  |      |  |      |  | H. rufum Fée  |   |  |   |  | H. trichophyllum Kunth  |   |  |  |   |  |   |  |      |  |      |  | H. plumosum Kaulf.  |   |  |   |  |      |  |      |  | H. consanguineum C.V.Morton  |   |  |   |  | H. microcarpum Desv.  |   |  |  |   |  |   |  |      |  |      |  | H. cocosense A.Rojas  |   |  |   |  | H. hirsutum (L.) Sw.  |   |  |  |   |  |   |  |      |  |      |  | H. saenzianum L.D.Gómez  |   |  |   |  | H. semiglabrum Rosenst.  |   |  |  |   |  |   |  |      |  | H. sieberi (C.Presl) Bosch  |   |  |   |  | H. trapezoidale Liebm.  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |   |  |      |  |      |  | H. crispum Kunth  |   |  |   |  | H. delicatulum Sehnem  |   |  |  |   |  |   |  |      |  | H. latifrons Bosch  |   |  |   |  |      |  |      |  | H. crassipetiolatum Stolze  |   |  |   |  | H. fragile (Hedw.) Morton  |   |  |  |   |  |   |  |      |  |      |  | H. ivohibense Tardieu  |   |  |   |  | H. splendidum Bosch  |   |  |  |   |  |   |  |      |  | H. elegans Spreng.  |   |  |   |  |      |  | H. lineare (Sw.) Sw.  |   |  |   |  | H. pulchellum Schltdl. & Cham.  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   | Sphaerocionium |  |   |  |  |   |  |   |  |      |  | H. recurvum Gaudich.  |   |  |   |  |      | (Mecodium) |      |  |      |  |      |  | H. mnioides Baker  |   |  |   |  |      |  | H. rarum R.Br. (Narrow filmy fern)  |   |  |   |  |      |  | H. novoguineense (Rosenst.) K.Iwats.  |   |  |   |  | H. ooides F.Muell. & Baker ex Baker  |   |  |  |   |  |  |   |  |  |   |  |   |  |      |  | H. cuneatum Kunze  |   |  |   |  |      |  | H. inaequale (Poir.) Desv.  |   |  |   |  |      |  | H. balfourii Baker  |   |  |   |  | H. capense Schrad.  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |   |  |      |  |      |  | H. myriocarpum Hook.  |   |  |   |  |      |  | H. apiculatum Mett. ex Kuhn  |   |  |   |  |      |  | H. protrusum Hook.  |   |  |   |  | H. undulatum (Sw.) Sw.  |   |  |  |   |  |  |   |  |  |   |  |   |  |      |  |      |  | H. kuhnii C.Chr.  |   |  |   |  | H. sibthorpioides (Bory ex Willd.) Mett. ex Kuhn  |   |  |  |   |  |   |  |      |  | H. corrugatum Christ  |   |  |   |  |      |  | H. wrightii Bosch  |   |  |   |  |      |  | H. bryoides C.W.Chen, Ebihara & K.Y.Cheng  |   |  |   |  |      |  |      |  | H. fujisanense Nakai  |   |  |   |  |      |  | H. polyanthos (Sw.) Sw. (Smooth filmy fern)  |   |  |   |  | H. punctisorum Rosenst.  |   |  |  |   |  |  |   |  |   |  |      |  | H. mikawanum (Seriz.) Seriz.  |   |  |   |  |      |  |      |  | H. fumarioides Bory ex Willd.  |   |  |   |  | H. paniculiflorum C.Presl  |   |  |  |   |  |   |  |      |  | H. longissimum (Ching & P.S.Chiu) K.Iwats.  |   |  |   |  | H. parallelocarpum Hayata  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |   | (Hymenophyllum) |      |  |      | section |      |  |      |  |      |  | H. armstrongii (Baker) Kuhn  |   |  |   |  | H. marginatum Hook. & Grev. (Bordered filmy fern)  |   |  |  |   |  |   |  |      |  | H. multifidum (G.Forst.) Sw.  |   |  |   |  |      |  | H. minimum A.Rich.  |   |  |   |  | H. pumilio Rosenst.  |   |  |  |   |  |  |   |  |  |   |  |   |  |      |  |      |  | H. pectinatum Cav.  |   |  |   |  |      |  | H. dentatum Cav. (Shushu-lahuén)  |   |  |   |  | H. dicranotrichum (C.Presl) Sadeb.  |   |  |  |   |  |  |   |  |   |  |      |  | H. caespitosum Gaudich.  |   |  |   |  |      |  | H. rugosum C.Chr. & Skottsb.  |   |  |   |  |      |  | H. cordobense (Hieron.) C.Larsen & Arana  |   |  |   |  | H. tunbrigense (L.) Sm. (Tunbridge‘s filmy fern)  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   | Hymenophyllum |  |   |  |   |  |      |  |      | subsection |      |  |      |  | H. simonsianum Hook.  |   |  |   |  |      |  | H. humbertii C.Chr.  |   |  |   |  | H. perrieri Tardieu  |   |  |  |   |  |  |   |  |   |  |  |   |  |  |   | Dimidiata |  |   |  |   |  |      | section |      |  |  |   |  |   |  |      |  |      |  | H. baileyanum Domin  |   |  |   |  |      |  | H. blandum Racib.  |   |  |   |  | H. deplanchei Mett. ex Kuhn  |   |  |  |   |  |  |   |  |   |  |  |   |  |  |   |  |  |   | Hemicyatheon |   | section |      |  |      |  | H. rolandi-principis Rosenst.  |   |  |   |  |      |  | H. dimidiatum Mett. ex Kuhn  |   |  |   |  | H. soriemersum Rouhan & C.Del Rio  |   |  |  |   |  |  |   |  |   |  |      |  |      |  | H. macgillivrayi (Baker) Copel.  |   |  |   |  | H. serrulatum (C.Presl) C.Chr.  |   |  |  |   |  |   |  |      |  |      |  | H. chamaecyparicola T.C.Hsu & Z.X.Chang  |   |  |   |  |      |  | H. devolii M.J.Lai  |   |  |   |  |      |  | H. exsertum Wall. ex Hook.  |   |  |   |  | H. oligosorum Makino  |   |  |  |   |  |  |   |  |  |   |  |   |  |      |  | H. praetervisum Christ  |   |  |   |  |      |  |      |  | H. fuscum (Blume) Bosch  |   |  |   |  | H. holochilum (Bosch) C.Chr.  |   |  |  |   |  |   |  |      |  | H. pachydermicum Ces.  |   |  |   |  |      |  | H. barbatum (Bosch) Baker  |   |  |   |  |      |  | H. acanthoides (Bosch) Rosenst.  |   |  |   |  | H. denticulatum Sw.  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   | Amphipterum |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |   |  |  |  | 
 Extinct species include: 
  See also
 - Trichomanes, the members of which are also called filmy ferns.
References
   - ^ "Hymenophyllum J.E.Sm". www.gbif.org. Retrieved 10 October 2022. 
- ^ Hassler, Michael (2004–2022). "Genus Hymenophyllum J.E.Sm". World Ferns. Synonymic Checklist and Distribution of Ferns and Lycophytes of the World. Version 14.1. Retrieved 2022-10-12. 
- ^ Nitta, Joel H.; Schuettpelz, Eric; Ramírez-Barahona, Santiago; Iwasaki, Wataru; et al. (2022). "An Open and Continuously Updated Fern Tree of Life". Frontiers in Plant Science. 13: 909768. doi:10.3389/fpls.2022.909768. PMC 9449725. PMID 36092417. 
- ^ "Tree viewer: interactive visualization of FTOL". FTOL v1.7.0 (GenBank release 261). 2024. Retrieved 1 May 2025. 
- ^ Pigg, K. B.; DeVore, M. L.; Greenwood, D. R.; Sundue, M. A.; Schwartsburd, P.; Basinger, J. F. (2021). "Fossil Dennstaedtiaceae and Hymenophyllaceae from the Early Eocene of the Pacific Northwest". International Journal of Plant Sciences. 182 (9): 793–807. doi:10.1086/715633. S2CID 239036762. 
  External links
   
 
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|  DomainArchaeaBacteriaEukaryota(major groupsMetamonadaDiscobaDiaphoretickes Hacrobia Cryptista
RhizariaAlveolataStramenopilesPlants
Amorphea AmoebozoaOpisthokonta AnimalsFungiMesomycetozoea)
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|  Kingdom Plant:RhodophytaChlorophytaMarchantiophytaBryophytaAnthocerotophytaPolypodiophytaAcrogymnospermaeAngiospermae
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| Taxon identifiers | 
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| Hymenophyllum |  | 
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