| | Ferns (Filicopsida) of Britain and Ireland |
“Royal Fern”.
Sporophyte. The rhizomes short, stout (massive); erect (emergent, so that emature plants may exhibit a small trunk of 30 cm or more); hairy, or naked (? - “not scaly”). Plants bearing markedly different fertile and sterile leaves.
Leaves aggregated terminally; to (30–)60–250(–400) cm long; complexly divided; bipinnate with more or less undivided pinnules, or bipinnate with more or less undivided pinnules to bipinnate with conspicuously divided pinnules (the pinnules of sterile leaves sometimes with a rounded lobe on the lower side at the base). Pinnae (5–)7–15(–17) on each side of the leaf (the 2–3 basal pairs fertile in the fertile leaves). The fertile leaves bipinnate with several pinnae, the lower (proximal) pinnae bearing normal green pinnules, but those of the upper (distal) pinnae non-laminate, more or less linear, and densely covered with sporangia. The petioles hairy when young, soon glabrous; vascularised via a single strand (this horseshoe shaped at the base, becoming half-moon shaped acroptally). The longest pinnae the lowermost to near the base of the blade (the sterile ones markedly decreasing in length acropetally). The venation of the lamina open (branching by repeated dichotomies, and reaching the margin).
Eusporangiate. The sporangia short-stalked and relatively massive, in non-indusiate, ill-defined clusters densely covering the fertile pinnules, brown; in the absence of laminae on the fertile pinnae, usually described as marginal; exposed; not aggregated into sori. The sporangial wall of several cell layers. The sporangia with an ‘annulus’ represented by a group of thick-walled cells on one side; dehiscing by a slit running across the apex from the lateral annulus.
Distribution and habitat. Helophytic to mesophytic. On peaty soil in fens, bogs, wet woods and heaths, and naturalized in ditches and hedgerows. Recorded throughout the British Isles and common in parts of western Britain and western Ireland, but absent from large areas of eastern Britain.
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, East Norfolk, West Norfolk, Bedfordshire, Northamptonshire, 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, Berwickshire, East Lothian, Midlothian, Fifeshire, Stirlingshire, West Perthshire, Mid Perthshire, Kincardineshire, 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 Sutherland, West Sutherland, Caithness, Outer Hebrides, 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 Osmundaceae (C.T.W.); Osmundaceae (Swale and Hassler); Osmundaceae (Stace). Order Osmundales (Swale and Hassler).
Illustrations. • Osmunda regalis: Eng. Bot. 1838 (1886). • Osmunda regalis: Sowerby and Johnson (1859). • Osmunda regalis: habit and vernation. Osmunda regalis. The photo at right shows fertile pinnae borne distally to sterile pinnae on the circinately uncoiling fertile leaves. Lower Moors, St. Mary's, Isles of Scilly. Giles Watson, 2005. • Osmunda regalis: details. Osmunda regalis: fertile pinna, ts near base of petiole, and sporangium showing the annulus. From Le Maour and Decaisne (1873). • Osmunda regalis (inter alia). Aspleniaceae. 1741, Asplenium adiantum-nigrum; 1742, Asplenium trichomanes; 1743, Asplenium viride; 1744, Asplenium marinum; 1745, Asplenium ruta-muraria; 1746, Aslpenium x-alternifolium (A. septentrionale x A. trichomanes); 1747, Asplenium septentrionale. 1748, Phyllitis scolopendrium. 1749, Ceterach officinarum. Pteridaceae. 1750, Anogramma leptophylla. Blechnaceae. 1751, Blechnum spicant. Hypolepidaceae. 1752, Pteridium aquilinum. Adiantaceae. 1753, Adiantum capillus-veneris. Hymenophyllaceae. 12754. Trichomanes speciosum; 1755, Hymenophyllum tunbrigense; 1756, Hymenophyllum wilsonii. OSMUNDACEAE. 157, Osmunda regalis. Ophioglossaceae. 1758, Botrychium lunaria; 1759, Ophioglossum vulgatum; 1760, Ophioglossum lusitanicum. From Sowerby and Johnson (1863, the family assignments following Swale and Hassler).
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, 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. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2004 onwards. Ferns (Filicopsida) of Britain and Ireland. Version: 5th August 2019. delta-intkey.com’.
