Belongs within: Leptosporangiatae.
Contains: Hymenophyllum, Trichomanes.
The Hymenophyllaceae include the filmy ferns, mostly small ferns that get their vernacular name from their thin translucent fronds, with blades generally only one cell thick. Generic subdivisions within this family have varied significantly between authors, but most recent studies agree on a basal division between broad Hymenophyllum and Trichomanes lineages. One of the largest species of Hymenophyllaceae, the kidney fern Cardiomanes reniforme, has been suggested to be the sister of all other Hymenophyllaceae, but Pryer et al. (2001) resolved it as the sister to the Hymenophyllum lineage. Cardiomanes reniforme is a New Zealand species bearing stiff, reniform laminae with veins radiating from a sinus and repeatedly forked (Allan 1961).
Characters (Smith et al. 2006): Terrestrial and epiphytic; rhizomes slender, creeping, wiry, or sometimes erect and stouter, protostelic; vernation circinate; blades usually one cell thick between veins; stomata lacking; cuticles lacking or highly reduced; scales usually lacking on blades, indument sometimes of hairs; sori marginal, indusia conical (campanulate), tubular, or clam-shaped (bivalvate), with receptacles (at least in trichomanoid genera) usually elongate, protruding from involucres; sporangia maturing graduately in basipetal fashion, each with an uninterrupted, oblique annulus; spores green, globose, trilete; gametophytes filamentous or ribbon-like, often reproducing by fragmentation or production of gemmae; x = 11, 12, 18, 28, 32, 33, 34, 36, and perhaps others.
<==Hymenophyllaceae [Hymenophyllales, Hymenophylleae, Hymenophylloideae]
| i. s.: Hymenoglossum cruentumPS01
| Rosenstockia rolandi-principisPS01
| HopetediaSS04
|--+--HymenophyllumPS01
| `--Cardiomanes Presl 1843PS01, A61 [Cardiomanoideae]
| `--*C. reniforme (Forster) Presl 1843A61 [=Trichomanes reniforme Forster 1786A61, Crepidomanes reniformeC06]
`--+--+--+--AbrodictyumSP09
| | | |--‘Trichomanes’ boninenseI77
| | | |--‘Trichomanes’ cumingianumI77
| | | `--A. elongatumSP09
| | |--‘Trichomanes’ subg. PachychaetumW96
| | | |--T. cupressoides [=Solenodesmium cupressoides]W96
| | | `--T. tamarisciforme [=Cephalomanes tamarisciformis, Macroglena tamarisciformis]PS01
| | `--CephalomanesSP09
| | |--C. atrovirensH90
| | |--C. javanicumSP09 [=Trichomanes javanicumW96]
| | |--‘Trichomanes’ oblongifoliumI77
| | `--C. obscurumI88
| `--TrichomanesSP09
`--+--Polyphlebium Cop. 1938SP09, A61
| |--P. borbonicumSP09
| `--P. endlicherianumSP09
`--+--DidymoglossumSP09
| | i. s.: D. curtii [=Trichomanes curtii]W96
| | ‘Trichomanes’ godmanii [=Microgonium godmanii]W96
| | D. petersii [=Trichomanes petersii]W96
| | ‘Trichomanes’ punctatum [=Crepidomanes punctatum]W96
| | D. reptans [=Trichomanes reptans]W96
| |--‘Trichomanes’ sect. MicrogoniumPS01
| | |--D. ekmaniiSP09 [=Microgonium ekmaniiPS01, Trichomanes ekmaniiPS01]
| | `--T. tahitenseI77 [=Microgonium tahitenseH90]
| `--+--D. krausiiSP09 [=Trichomanes krausiiW96]
| |--D. membranaceumSP09 [=Lecanium membranaceumPS01, Trichomanes membranaceumPS01]
| `--D. pinnatinervium [=Trichomanes pinnatinervium]PS01
`--+--Vandenboschia Cop. 1938SP09, A61 [incl. Trichomanes sect. Lacosteopsis Morton 1968PS01]
| |--V. radicans (Swartz) Copel. 1938SP09, I88 (see below for synonymy)
| | |--V. r. var. radicansI88
| | `--‘Crepidomanes’ r. var. naseanum (Christ) Iwats. 1985 [=Trichomanes naseanum Christ 1905]I88
| `--V. speciosa [=Crepidomanes speciosum, Trichomanes radicans var. speciosum]PS01
`--CrepidomanesSP09
|--C. thysanostomumSP09
`--+--Crepidomanes subg. CrepidomanesPS01
| |--C. (sect. Taschneria) bipunctatumPS01, SP09 [=Trichomanes bipunctatum Poir. in Lamarck 1808A61]
| |--‘Trichomanes’ christiiI77
| |--C. latealatum (v. d. B.) Copel. 1938I88 (see below for synonymy)
| `--‘Trichomanes’ tosaeI77
`--C. minutum (Blume) Iwats. 1985SP09, I88 (see below for synonymy)
Crepidomanes latealatum (v. d. B.) Copel. 1938I88 [=Didymoglossum latealatum v. d. B. 1863I88; incl. Hymenophyllum filiculaBS-V28, Trichomanes filiculaI88, Didymoglossum insigne v. d. B. 1863I88, Crepidomanes insigne (v. d. B.) Fu 1957I88, Trichomanes bipunctatum var. insigne (v. d. B.) Bedd. 1883I88, T. insigne (v. d. B.) Bedd. 1868I88]
Crepidomanes minutum (Blume) Iwats. 1985SP09, I88 [=Trichomanes minutum Blume 1828PS01, I88, Gonocormus minutus (Blume) v. d. B. 1861I88; incl. T. diffusum Blume 1828I88, G. diffusus (Blume) v. d. B. 1861I88, T. proliferum Blume 1828I88]
Vandenboschia radicans (Swartz) Copel. 1938SP09, I88 [=Trichomanes (sect. *Lacosteopsis) radicans Swartz 1801PS01, I88, Crepidomanes radicansI88]
*Type species of generic name indicated
References
[A61] Allan, H. H. 1961. Flora of New Zealand vol. 1. Indigenous Tracheophyta: Psilopsida, Lycopsida, Filicopsida, Gymnospermae, Dicotyledones. R. E. Owen, Government Printer: Wellington (New Zealand).
[BS-V28] Bory de Saint-Vincent, J. B. 1828. Voyage Autour du Monde, Exécuté par Ordre du Roi, Sur la Corvette de Sa Majesté, La Coquille, pendant les années 1822, 1823, 1824 et 1825. Botanique. Cryptogamie. Arthus Bertrand: Paris.
[C06] Cheeseman, T. F. 1906. Manual of the New Zealand Flora. John Mackay, Government Printer: Wellington.
[H90] Harden, G. J. (ed.) 1990. Flora of New South Wales vol. 1. New South Wales University Press.
[I77] Iwatsuki, K. 1977. Studies in the systematics of filmy ferns III. An observation on the involucres. Botanical Magazine, Tokyo 90: 259–267.
[I88] Iwatsuki, K. 1988. An enumeration of the pteridophytes of Nepal. In: Ohba, H., & S. B. Malla (eds) The Himalayan Plants vol. 1. The University Museum, University of Tokyo, Bulletin 31: 231–339.
[PS01] Pryer, K. M., A. R. Smith, J. S. Hunt & J. Y. Dubuisson. 2001. rbcL data reveal two monophyletic groups of filmy ferns (Filicopsida: Hymenophyllaceae). American Journal of Botany 88 (6): 1118–1130.
[SS04] Schneider, H., E. Schuettpelz, K. M. Pryer, R. Cranfill, S. Magallón & R. Lupia. 2004. Ferns diversified in the shadow of angiosperms. Nature 428: 553–557.
[SP09] Schuettpelz, E., & K. M. Pryer. 2009. Evidence for a Cenozoic radiation of ferns in an angiosperm-dominated canopy. Proceedings of the National Academy of Sciences of the USA 106 (27): 11200–11205.
[W96] Wallace, J. W., Jr. 1996. Chemotaxonomy of the Hymenophyllaceae. II. C-glycosylflavones and flavone-O-glycosides of Trichomanes s.l. American Journal of Botany 83: 1304–1308.
Smith, A. R., K. M. Pryer, E. Schuettpelz, P. Korall, H. Schneider & P. G. Wolf. 2006. A classification for extant ferns. Taxon 55 (3): 705–731.