# Hymenophyllum

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:
| Phylogeny of Hymenophyllum | Unassigned species: |
| (Myrmecostylum) H. scabrum A.Rich. H. sanguinolentum (G.Forst.) Sw. (Piripiri) H. villosum Colenso H. plicatum Kaulf. H. seselifolium C.Presl H. tortuosum Hook. & Grev. (Pleuromanes) H. pallidum (Blume) Ebihara & K.Iwats. H. leratii Rosenst. H. flabellatum Labill. (Shiny filmy fern) H. rufescens Kirk (Hymenoglossum) H. cruentum Cav. (Helecho película) H. asplenioides (Sw.) Sw. H. heimii Tardieu H. paniense Ebihara & K.Iwats. (Diplophyllum) H. dilatatum (G.Forst.) Sw. (Cardiomanes) H. nephrophyllum Ebihara & K.Iwats. (Kidney fern) (Fuciformia) H. fuciforme Sw. H. pulcherrimum Colenso (Globosa) H. badium Hook. & Grev. H. demissum (G.Forst.) Sw. H. caudiculatum Mart. (Pallante chilote) H. pluviatile Perrie & Brownsey H. australe Willd. (Austral filmy ferm) H. fucoides (Sw.) Sw. H. flexuosum A.Cunn. H. gracilescens Domin H. imbricatum Blume 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. crassipetiolatum Stolze H. crispum Kunth H. delicatulum Sehnem H. ivohibense Tardieu H. splendidum Bosch H. fragile (Hedw.) Morton H. latifrons Bosch H. elegans Spreng. H. lineare (Sw.) Sw. H. pulchellum Schltdl. & Cham. H. saenzianum L.D.Gómez H. semiglabrum Rosenst. H. sieberi (C.Presl) Bosch H. trapezoidale Liebm. 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. corrugatum Christ H. kuhnii C.Chr. H. sibthorpioides (Bory ex Willd.) Mett. ex Kuhn 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 H. ectocarpon Fée H. peltatum (Poir.) Desv. (Alpine filmy fern) H. falklandicum Baker (Falklands filmy fern) H. secundum Hook. & Grev. H. wilsonii Hook. (Wilson´s filmy fern) Dimidiata section H. triangulare Baker H. cupressiforme Labill. (Common filmy fern) H. pumilum C.Moore H. baileyanum Domin H. blandum Racib. H. deplanchei Mett. ex Kuhn H. feejeense Brack. H. bivalve (G.Forst.) Sw. H. revolutum Colenso 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 | Hymenophyllum abruptum Hook. Hymenophyllum acutum (C.Presl) Ebihara & K.Iwats. Hymenophyllum adiantoides Bosch Hymenophyllum aeruginosum (Poir.) Carmich. Hymenophyllum alveolatum C.Chr. Hymenophyllum amabile Morton Hymenophyllum andinum Bosch Hymenophyllum angulosum Christ Hymenophyllum angustum Bosch Hymenophyllum antillense (Jenman) Jenman Hymenophyllum applanatum (A.M.Gray & R.G.Williams) Ebihara & K.Iwats. Hymenophyllum apteryx M.Kessler & Sundue Hymenophyllum archboldii (Copel.) C.V.Morton Hymenophyllum assurgens M.Kessler & A.R.Sm. Hymenophyllum axillare Sw. Hymenophyllum bartlettii (Copel.) C.V.Morton Hymenophyllum batuense Rosenst. Hymenophyllum bicolanum Copel. Hymenophyllum bontocense Copel. Hymenophyllum brachyglossum A.Braun ex Kunze Hymenophyllum brachypus Sodiro Hymenophyllum brassii C.Chr. Hymenophyllum brevifrons Kunze Hymenophyllum brevistipes Liebm. Hymenophyllum bryophilum C.Chr. Hymenophyllum caparaoense Brade Hymenophyllum capillaceum Roxb. Hymenophyllum capurroi de la Sota Hymenophyllum cardunculus C.Chr. Hymenophyllum compactum Bonap. Hymenophyllum copelandii C.V.Morton Hymenophyllum crispatoalatum Hayata Hymenophyllum crispatum Wall. ex Hook. & Grev. Hymenophyllum cristatum Hook. & Grev. Hymenophyllum darwinii Hook.fil. Hymenophyllum deltoideum C.Chr. Hymenophyllum densipilosum A.Rojas Hymenophyllum dependens C.V.Morton Hymenophyllum diversilobum (C.Presl) Fée Hymenophyllum eboracense Croxall Hymenophyllum edanoi (Copel.) C.V.Morton Hymenophyllum edentulum (Bosch) C.Chr. Hymenophyllum elbertii Rosenst. Hymenophyllum elongatum J.W.Grimes Hymenophyllum emarginatum Sw. Hymenophyllum exquisitum T.C.Hsu & Y.S.Chao Hymenophyllum farallonense Hieron. Hymenophyllum fendlerianum Sturm Hymenophyllum ferax Bosch Hymenophyllum fimbriatum J.Sm. Hymenophyllum firmum Alderw. Hymenophyllum foersteri Rosenst. Hymenophyllum foxworthyi Copel. Hymenophyllum francii (Christ) Ebihara & K.Iwats. Hymenophyllum gardneri Bosch Hymenophyllum geluense Rosenst. Hymenophyllum glaziovii Baker Hymenophyllum gorgoneum Copel. Hymenophyllum hallieri Rosenst. Hymenophyllum hastatum A.Rojas Hymenophyllum helicoideum Sodiro Hymenophyllum hemidimorphum R.C.Moran & B.Øllg. Hymenophyllum hemipteron Rosenst. Hymenophyllum herzogii Rosenst. Hymenophyllum hieronymi (Brause) C.Chr. Hymenophyllum hirtellum Sw. Hymenophyllum horizontale C.V.Morton Hymenophyllum hosei Copel. Hymenophyllum humboldtianum E.Fourn. Hymenophyllum integrivalvatum C.Sánchez Hymenophyllum interruptum Kunze Hymenophyllum involucratum Copel. Hymenophyllum jamesonii Hook. Hymenophyllum jimenezii A.R.Sm. & M.Kessler Hymenophyllum johorense Holttum Hymenophyllum junghuhnii Bosch Hymenophyllum kaieteurum Jenman Hymenophyllum karstenianum J.W.Sturm Hymenophyllum kerianum Watts Hymenophyllum klabatense Christ Hymenophyllum krauseanum Phil. Hymenophyllum l´herminieri Mett. ex Kuhn Hymenophyllum lamellatum Stolze Hymenophyllum laminatum Copel. Hymenophyllum lanatum Fée Hymenophyllum latisorum M.Kessler & A.R.Sm. Hymenophyllum laxum (Copel.) C.V.Morton Hymenophyllum ledermannii Brause Hymenophyllum lehmannii Hieron. Hymenophyllum leptocarpum Copel. Hymenophyllum levingei C.B.Clarke Hymenophyllum lindenii Hook. Hymenophyllum lobatoalatum Klotzsch Hymenophyllum lobbii Moore ex Bosch Hymenophyllum longifolium Alderw. Hymenophyllum macroglossum Bosch Hymenophyllum macrosorum Alderw. Hymenophyllum macrothecum Fée Hymenophyllum maderense Gibby & Lovis Hymenophyllum matthewsii Bosch Hymenophyllum maxonii Christ ex Morton Hymenophyllum megistocarpum (Copel.) C.V.Morton Hymenophyllum melanosorum (Copel.) C.V.Morton Hymenophyllum microchilum (Baker) C.Chr. Hymenophyllum mirificum Morton Hymenophyllum molle C.V.Morton Hymenophyllum mortonianum Lellinger Hymenophyllum mossambicense (Schelpe) Schippers Hymenophyllum multialatum C.V.Morton Hymenophyllum multicristatum A.Rojas Hymenophyllum nahuelhuapiense Diem & J.S.Licht. Hymenophyllum nanostellatum Lellinger Hymenophyllum nanum Sodiro Hymenophyllum nitiduloides Copel. Hymenophyllum nutantifolium Alderw. Hymenophyllum ovatum Copel. Hymenophyllum pantotactum Alderw. Hymenophyllum paucicarpum Jenman Hymenophyllum penangianum Matthew & Christ ex Christ Hymenophyllum perparvulum Alderw. Hymenophyllum pilosum Alderw. Hymenophyllum platylobum Bosch Hymenophyllum plumieri Hook. & Grev. Hymenophyllum pollemonianum Rosenst. Hymenophyllum prionema Kunze Hymenophyllum proctoris C.Sánchez Hymenophyllum productum Kunze Hymenophyllum pyramidatum Desv. Hymenophyllum quetrihuense Diem & J.S.Licht. Hymenophyllum ramosii Copel. Hymenophyllum reinwardtii Bosch Hymenophyllum ringens Christ Hymenophyllum roraimense C.V.Morton Hymenophyllum rubellum Rosenst. Hymenophyllum rufifolium Alderw. Hymenophyllum rufifrons Alderw. Hymenophyllum ruizianum (Klotzsch) Kunze Hymenophyllum salakense Racib. Hymenophyllum sampaioanum Brade & Rosenst. Hymenophyllum semialatum T.C.Hsu Hymenophyllum senterreanum Dubuisson & Deblauwe Hymenophyllum seramense K.Iwats., M.Kato & Ebihara Hymenophyllum sericeum (Sw.) Sw. Hymenophyllum silvaticum C.V.Morton Hymenophyllum silveirae Christ Hymenophyllum simplex C.V.Morton Hymenophyllum sodiroi C.Chr. Hymenophyllum stenocladum (Ching & P.S.Chiu) K.Iwats. Hymenophyllum subdemissum Christ Hymenophyllum subrigidum Christ Hymenophyllum superbum Morton Hymenophyllum taiwanense (Tagawa) C.V.Morton Hymenophyllum talamancanum A.Rojas Hymenophyllum taliabense Alderw. Hymenophyllum tarapotense Stolze Hymenophyllum tayloriae Farrar & Raine (Taylor’s filmy fern) Hymenophyllum tegularis (Desv.) Proctor & Lourteig Hymenophyllum tenerum Bosch Hymenophyllum thuidium Harr. Hymenophyllum todjambuense Kjellb. Hymenophyllum tomaniiviense (Brownlie) Ebihara & K.Iwats. Hymenophyllum treubii Racib. Hymenophyllum trichomanoides Bosch Hymenophyllum trichophorum (Alderw.) Ebihara & K.Iwats. Hymenophyllum trifoliatum (L.) Proctor & Lourteig Hymenophyllum turquinense C.Sánchez Hymenophyllum umbratile Diem & J.S.Licht. Hymenophyllum urbanii Brause Hymenophyllum valvatum Hook. & Grev. Hymenophyllum verecundum Morton Hymenophyllum veronicoides C.Chr. Hymenophyllum vestitum (C.Presl) Bosch Hymenophyllum viguieri Tardieu Hymenophyllum vittatum Copel. Hymenophyllum walleri Maiden & Betche Hymenophyllum whitei Goy |
Extinct species include:
* †Hymenophyllum axsmithii Pigg et al (Ypresian, Eocene Okanagan Highlands North America)