British ferns (Filicopsida)


L. Watson and M. J. Dallwitz

Athyrium filix-femina (L.) Roth


Asplenium filix-femina (L.) Roth.

Sporophyte. The rhizomes stout; short, more or less erect; bearing scales (these large, lanceolate, soft, and brown).

Leaves aggregated terminally; to 40–120(–150) cm long; dying in the autumn; compound; complexly divided; bipinnate with conspicuously divided pinnules (usually), or tripinnate with undivided ultimate pinnules (the pinnules more or less contiguous, pinnately lobed to pinnatifid). Pinnae about 15–30 on each side of the leaf (“up to 30”). Leaves not conspicuously bent near the junction of rachis and petiole. The petioles shorter than the blades (scaly at least below, with lanceolate, brown scales); about 0.25–0.5 x the length of the blade (a quarter to a third as long, green or purplish-red); vascularised via a single strand (this gutter-shaped, representing either a single leaf trace arising from the lower angle of the leaf gap, or fusion of a pair?). Leaf blades in outline lanceolate (tapered abruptly to the acuminate apex). The longest pinnae around the middle of the blade; 3–25 cm long (the lower ones considerably shorter). The pinnae decreasing markedly in length towards the base of the blade, the basal ones relatively short (the lower pinnae opposite and remote). The adjacent pinnae approximated but not strongly overlapping (in the upper rart of the leaf), or distant from one another and not at all overlapping (in the lower part). The venation of the lamina open.

The sporangia superficial; aggregated in sori. The sori elongated (oblong to linear, curved or J-shaped on larger pinnules, each on a receptacle with a vascular strand from the vein, borne one per pinnule segment in rows down either side of the pinnule, nearer its midrib than its margin); remaining discrete at maturity; with a true indusium. The indusia often exhibiting two forms on the same frond, attached on one side along a vein, or reniform and attached at the indentation (then bent on the lower margin, J- or C-shaped); persistent, covering the sorus till the spores are ripe, whitish, toothed. Paraphyses present in the sporangia. The mature spores monolete; with a perispore.

Distribution and habitat. Helophytic to mesophytic; on neutral substrates and on acid substrates (calcifuge). Calcifuge, in marshes, damp woods, shady hedgebanks, and rocky places including montane screes. Common throughout most of the British Isles.

Vice-county records. Britain: West Cornwall, East Cornwall, South Devon, North Devon, South Somerset, North Somerset, North Wiltshire, South Wiltshire, Dorset, Isle of Wight, South Hampshire, North Hampshire, West Sussex, East Sussex, East Kent, West Kent, Surrey, South Essex, North Essex, Hertfordshire, Middlesex, Berkshire, Oxfordshire, Buckinghamshire, East Suffolk, West Suffolk, East Norfolk, West Norfolk, Cambridgeshire, Bedfordshire, Huntingdonshire, Northamptonshire, East Gloucestershire, West Gloucestershire, Monmouthshire, Herefordshire, Worcestershire, Warwickshire, Staffordshire, Shropshire, Glamorgan, Breconshire, Radnorshire, Carmarthenshire, Pembrokeshire, Cardiganshire, Montgomeryshire, Merionethshire, Caernarvonshire, Denbighshire, Flintshire, Anglesey, South Lincolnshire, North Lincolnshire, Leicestershire, Nottinghamshire, Derbyshire, Cheshire, South Lancashire, West Lancashire, South-east Yorkshire, North-east Yorkshire, South-west Yorkshire, Mid-west Yorkshire, North-west Yorkshire, Durham, South Northumberland, North Northumberland, Westmorland, Cumberland, Isle of Man, Dumfriesshire, Kirkcudbrightshire, Wigtownshire, Ayrshire, Renfrewshire, Lanarkshire, Peeblesshire, Selkirkshire, Roxburghshire, Berwickshire, East Lothian, Midlothian, West Lothian, Fifeshire, Stirlingshire, West Perthshire, Mid Perthshire, East Perthshire, Angus, Kincardineshire, South Aberdeenshire, North Aberdeenshire, Banffshire, Moray, East Inverness-shire, West Inverness-shire, Argyll Main, Dunbartonshire, Clyde Isles, Kintyre, South Ebudes, Mid Ebudes, North Ebudes, West Ross, East Ross, East Sutherland, West Sutherland, Caithness, Outer Hebrides, Orkney islands, Shetland, Channel Islands. Ireland: South Kerry, North Kerry, West Cork, Mid Cork, East Cork, Waterford, South Tipperary, Limerick, Clare, North Tipperary, Kilkenny, Wexford, Carlow, Leix, South-east Galway, West Galway, North-east Galway, Offaly, Kildare, Wicklow, Dublin, Meath, West Meath, Longford, Roscommon, East Mayo, West Mayo, Sligo, Leitrim, Cavan, Louth, Monaghan, Fermanagh, East Donegal, West Donegal, Tyrone, Armagh, Down, Antrim, Londonderry.

Classification. Family Polypodiaceae (C.T.W.); Athyriaceae (Swale and Hassler); Woodsiaceae (Stace). Order Athyriales (Swale and Hassler).

Illustrations. • A. filix-femina: as A. felix-femina, Eng. Bot. 1869 (1886). • A. filix-femina: Sowerby and Johnson (1859). • Athyrium distentifolium and A. filix-femina (inter alia).

To view the illustrations with detailed captions, go to the interactive key. This also offers full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2004 onwards. British ferns (Filicopsida). Version: 4th January 2012.’.