Links to genera Ferns and Horsetails (Monilophytes) Clubmosses and Quillworts (Lycophytes)
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| Adiantum capillus-veneris • Maidenhair Fern
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| Adiantum capillus-veneris L.; Maidenhair Fern
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A small to medium-small fern with distinct and distinctive fan-shaped or wedge-shaped leaf segments, found mostly in western coastal sites on calcareous rocks; also naturalized on walls in frost-free situations.
habit: often pendulous and hanging from vertical or near-vertical surfaces, or erect when growing in horizontal situations such as limestone pavement. Plants develop in loose clusters from a short, creeping rhizome, and generally die back in winter, but may remain green in sheltered sites.
size: up to 30cm (rarely up to 45cm).
leaf: fan-shaped to wedge-shaped; pink to reddish when young, bright pale green when mature; technically 1-3 pinnate, the individual pinnae looking like separate leaves, each more or less notched on the outer edge, quite variable in size as well as amount and depth of notching; ends of fertile leaves folded under to form indusium; ends of sterile leaves more or less crenate (round-toothed) as well as notched; veins fanning out from base of pinnae, evenly branched, without midrib.
rhachis: fine, black to dark brown, shiny.
stipe: fine, black to dark brown, shiny, with a few scales near the base.
scales: at base of stipe only, dark brown, latticed (clathrate), narrowly triangular and attenuated.
sori: towards margin of pinnae, at ends of veins.
indusium: formed from the folded over ends of the pinnules.
spores: 3-sided (trilete); no perispore (thickened outer layer).
chromosome number: 2n=60, diploid.
identifying features: overall appearance is highly distinctive and unlike any other native British or Irish fern. Fan/wedge shaped leaf-segments, and rolled-under segment margins forming "false" indusia. Fine blackish stipe and rhachis.
habitat: on damp calcareous rocky substrates in mild, frost-free environments: natural sites include sea-cliffs away from direct spray, and limestone pavements near the coast; man-made ones such as mortared walls - often found self-sown on brick bases of greenhouses.
range: South-western coastal areas of Britain from Dorset west and north to South Wales; Cumbria; Isle of man; Channel Islands; western coastal areas of Ireland as far north as Donegal, also Kilkenny; naturalized in man-made habitats, often away from the coast in damp, frost-free environments.
conservation status: nationally scarce
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| Mature fronds, cultivated material |
 | Underside of pinnules showing rolled-under margins forming false indusia. Cultivated material, June |
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| Mature fronds, Cornwall, September |
 | Mature fronds, Cornwall, September |
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| Cornwall, September |
 | Cornwall, September |
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| Plant, escape from cultivation, naturalized on walls at Oxford Botanic Garden |
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Plant, escape from cultivation, naturalized on walls at Oxford Botanic Garden. Note small frond of Pteris vittata (Ladder Brake), lower right. |
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| On limestone rocks by the sea, Cumbria (Westmorland)
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With Anogramma leptophylla. Sao Miguel, Azores |
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