Hymenophyllaceae Mart.
  • Consp. Regn. Veg. 3. 1835. (Sep-Oct 1835)
  • Filmy Fern Family

This taxon is accepted by World Flora Online consortium
Notes: More details could be found in The Plant List v.1.1. Originally in The Plant List v.1.0

General Description

Plants epiphytic, terrestrial, or on rock. Stems long-creeping, often threadlike and intertwining, or short-erect, protostelic, bearing brown hairs of 1--2 types. Roots sparse or absent. Leaves small, 0.5--20 × 0.2--5 cm, often forming dense mats. Petiole short, threadlike to wiry, often winged part or entire length. Blade ovate or oblong to lanceolate, simple to decompound, usually 1 cell thick between veins (except Trichomanes membranaceum Linnaeus), entire or dentate; scales or simple and/or stellate hairs often borne on veins or leaf margins. Veins free and divergent, occasionally present as unattached "false" veins. Sori marginal on vein ends, enclosed by 2-valved or conic involucres. Sporangia borne on moundlike receptacle or on elongate "bristle," sessile or short-stalked; annulus oblique. Spores green, globose, trilete. Gametophytes filamentous or ribbonlike or a combination of both, much branched, 0.2--1 cm, often bearing gemmae, persistent, clone-forming by vegetative reproduction.

Plants epiphytic, petrophilous, or terrestrial, small to medium-sized. Rhizome sometimes short and erect, but usually slender and long creeping, often covered with hairs when young, simple or sometimes irregularly branching. Lamina simple to pinnately decompound, or flabellate, digitate, dichotomous, or even irregularly divided. Segments with a single veinlet, cells in one layer, or rarely with 2-4 cell layers without intercellular spaces and stomata. Sori terminal on veins, solitary, at apex of ultimate segments, or marginal on simple to pinnatifid fronds; involucres cup-shaped to deeply 2-cleft nearly to base; receptacles terminating a vein, short, capitate or clavate, or long and projecting; sporangia shortly stalked to (sub)sessile, maturing basipetally; annulus oblique, not interrupted; dehiscence irregular; spores globose-trilete, tetrahedral, containing chloroplasts, usually short-lived. x = 8, 11, 12, 13, 17, 21, 22, 26, 28, 36, 54 (base numbers x = 8, 54 are doubtful).


Roots often wanting and replaced by root hairs arising direct from the rhizome or lamina

Delicate herbs with short, erect or slender wide–creeping protostelic rhizomes, with hairs on young parts



Farrar, D. R. 1967. Gametophytes of four tropical fern genera reproducing independently of their sporophytes in the southern Appalachians. Science 155: 1266--1267. Farrar, D. R. 1985. Independent fern gametophytes in the wild. Proc. Roy. Soc. Edinburgh, B 86: 361--369. Morton, C. V. 1968. The genera, subgenera, and sections of the Hymenophyllaceae. Contr. U.S. Natl. Herb. 38: 153--214. Stokey, A. G. 1940. Spore germination and vegetative stages of the gametophytes of Hymenophyllum and Trichomanes. Bot. Gaz. 101: 759--790.

Common Names

Filmy Fern Family

 Information From

Flora of North America @ efloras.org
'Flora of North America @ eFloras (2008). Published on the Internet http://www.efloras.org/flora_page.aspx?flora_id=1 [accessed August 2016]' Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
  • A Flora of North America Association
Flora Of CHina @ efloras.org
'Flora of China @ eFloras (2008). Published on the Internet http://www.efloras.org/flora_page.aspx?flora_id=2 [accessed August 2016]' Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
  • B Missouri Botanical Garden
Plants Of the World Online Portal
  • C The Trustees of the Royal Botanic Gardens, Kew
World Flora Online Data. 2017.
  • D CC0 1.0 Universal (CC0 1.0).
World Flora Online consortium
World Flora Online Data. 2018.
  • E CC0 1.0 Universal (CC0 1.0).