Hymenophyllaceae Mart.

First published in Consp. Regn. Veg. [Martius] 3. 1835 [Sep-Oct 1835] , as 'Hymenophylleae' (1835)
This family is accepted

Descriptions

Hymenophyllaceae, Henk Beentje. Flora of Tropical East Africa. 2008

Morphology General Habit
Epiphytic, lithophytic or terrestrial ferns of medium to small size.
Vegetative Multiplication Rhizomes
Rhizome usually creeping, seldom erect, bearing hairs
Morphology Leaves Stipes
Stipe terete, not articulated, often with a single leaf trace.
Morphology Leaves Leaf lamina
Lamina simple to pinnately compound to irregularly divided; segments single-veined, lamina usually a single cell thick, lacking stomata.
Morphology Leaves Leaf veins
Veins free or joining to form a submarginal vein; false veins, unconnected with the real ones, sometimes present
Morphology Reproductive morphology Sori
Sori terminal on veins, solitary at apex of terminal segments or marginal on simple to pinnatifid fronds; involucre cup-shaped to deeply 2-cleft; sporangia shortstalked to (sub-)sessile, maturing basipetally and carried on receptacles terminating a vein, these short, capitate or clavate to long and exserted; annulus oblique, not interrupted; dehiscence irregular
Morphology Reproductive morphology Spores
Spores globose-trilete, tetrahedral, containing chloroplasts, usually short-lived.
Ecology
The family is most diverse in the mossy montane forests of the tropics and south-temperate areas.
Note
Here I follow the recent treatment by A. Ebihara, J.-Y. Dubuisson, K. Iwatsuki, S. Hennequin & M. Ito in Blumea 51, 2: 221–280 (2006), which is based on a worldwide revision based on molecular data, and which is an approach which tries to recognise natural (monophyletic) as well as morphologically recognizable groups. This supersedes the slightly older work by Iwatsuki in Families & genera of vascular plants 1: 157–163 (1990), taken up in recent Floras such as Flora of Australia 48 (1998) and by Roux in Conspectus of southern African Pteridophyta (2001). 600 species in either two genera ( Trichomanes and Hymenophyllum) or into various more ‘natural’ genera.
[FTEA]

Timothy Utteridge & Gemma Bramley (2020). The Kew Tropical Plant Families Identification Handbook, Second Edition. Kew Publishing Royal Botanic Gardens, Kew

Note
Small epiphytic or epilithic ferns. Lamina translucent only one cell thick. Sporangia born at vein tip on leaf margin, helically on an elongating narrow column or shorter receptacle between two flaps or in a trumpet-like indusium.
Recognition
Characters of similar families: Aspleniaceae: leaves thick (i.e. not translucent), indusium an elongated flap running along veins. Polypodiaceae: leaves thick, articulated to a persistent stipe base, leaves often dimorphic, indusium lacking. Thelypteridaceae: medium-sized terrestrial ferns with stout pinnate leaves, stiff, colourless hairs present. Adiantaceae: true indusium-lacking sporangia borne on abaxial surface of a false indusium formed from the reflexed leaf margin. Grammitidaceae: small epiphytic ferns, leaves thick, indusium lacking.
Morphology General Habit
Delicate epiphytic, epilithic or terrestrial ferns, small 0.2–70 cm (rarely to 2 m, and these pendulous)
Vegetative Multiplication Rhizomes
Rhizomes slender, creeping or erect, often wiry
Morphology General Indumentum
Indumentum of scales or simple and/or stellate brown hairs, often on veins or leaf margins
Morphology Leaves
Fronds simple or variously divided, often very different in outline and size on species with creeping rhizomes, erect or pendulous, lamina usually 1 cell thick (rarely more than 1 cell thick) and translucent, without stomata, with free veins or the veins joining a submarginal vein
Morphology Reproductive morphology Sori
Sori marginal on vein ends within a bivalve, tubular or obconic (trumpet-shaped) indusial-Sporangia borne on mound-like or on elongate narrow column-like receptacles; spores green (chlorophyllous), trilete, globose.
Distribution
A natural family, with approximately 600 species traditionally placed in two genera (Trichomanes and Hymenophyllum), but the most recent classification (Ebihara et al. 2006) uses 9 genera. Historically, floristic treatments from different areas used dissimilar classifications: New World 6 genera, Africa 47 genera and Asia 34 genera. 95% of the species in the tropics.
Ecology
Almost all in ever-wet habitats (heavy rainfall and/or high humidity), some species in temperate rain forests, e.g. New Zealand.
Description Author
Timothy Utteridge and Peter Edwards
[KTROP-FIH]

Hymenophyllaceae, A.H.G Alston. Flora of West Tropical Africa. 1959

Morphology General Habit
Delicate herbs with short, erect or slender wide–creeping protostelic rhizomes, with hairs on young parts
Morphology Roots
Roots often wanting and replaced by root hairs arising direct from the rhizome or lamina
[FWTA]

Sources

  • Flora of Tropical East Africa

    • Flora of Tropical East Africa
    • http://creativecommons.org/licenses/by-nc-sa/3.0

  • Flora of West Tropical Africa

    • Flora of West Tropical Africa
    • http://creativecommons.org/licenses/by-nc-sa/3.0

  • Herbarium Catalogue Specimens

    • 'The Herbarium Catalogue, Royal Botanic Gardens, Kew. Published on the Internet http://www.kew.org/herbcat [accessed on Day Month Year]'. Please enter the date on which you consulted the system.

  • Kew Names and Taxonomic Backbone

    • The International Plant Names Index and World Checklist of Vascular Plants 2025. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 International Plant Names Index and World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0

  • The Kew Tropical Plant Families Identification Handbook

    • The Kew Tropical Plant Families Identification Handbook
    • http://creativecommons.org/licenses/by-nc-sa/3.0