British ferns (Filicopsida)

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L. Watson and M. J. Dallwitz

Polystichum setiferum (Forsk.) Woynar

“Soft Shield-fern”.

Aspidium angulare Kit. ex Willd., P. setiferum (Willd.) C. Presl.

Sporophyte. The rhizomes stout; ascending to erect; bearing scales.

Leaves aggregated terminally; to 40–150 cm long; persistent to dying in the autumn (sub-persistent); circinnate; compound; complexly divided; bipinnate with conspicuously divided pinnules (the pinnae fully pinnate, the pinnules with a rounded or deltoid basal lobe). Pinnae about 30–40 on each side of the leaf. The petioles shorter than the blades (about a quarter to half as long, clothed with ovate-lanceolate brown scales); vascularised by several discrete strands (derived via several leaf traces). Leaf blades in outline lanceolate; ‘herbaceous’ (flaccid). The longest pinnae around the middle of the blade (the lowest pinnae much shorter or nearly as long as the longest, depending which flora one relies on); about 6–8 cm long. The venation of the lamina open.

The sporangia superficial; protected; aggregated in sori. The sori sub-orbicular (about 0.5–1 mm in diameter); remaining discrete at maturity (in a row down each side of the midrib of the pinnule and of its basal lobe, with the vein upon which the sorus is borne not or only shortly continued beyond it); with a true indusium. The indusia peltate. The mature spores monolete; with a perispore.

Distribution and habitat. Woods and hedgebanks in moist places. Channel Islands, S and W Britain and Ireland, rarer in the NE and absent from northern and eastern Scotland.

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, East Perthshire, Kincardineshire, Moray, East Inverness-shire, West Inverness-shire, Argyll Main, Dunbartonshire, Clyde Isles, Kintyre, South Ebudes, Mid Ebudes, North Ebudes, West Ross, Outer Hebrides, 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.); Dryopteridaceae (Swale and Hassler); Dryopteridaceae (Stace). Order Dryopteridales (Swale and Hassler).

Sterile hybrids, intermediate between the parents in form, are P. x bicknellii (Christ) Hahne = P. setiferum x P. aculeatum; P. x lonchitiforme (Halacsy) Bech. = P. setiferum x P. lonchitis.

Illustrations. • P. setiferum: as P. angulare, Eng. Bot. 1861 (1886). • P. setiferum: Sowerby and Johnson (1859). • 9 British Dryopteridaceae (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. http://delta-intkey.com’.

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