British ferns (Filicopsida)


L. Watson and M. J. Dallwitz

Dryopteris oreades Formin

“Mountain Male Fern”.

Dryopteris abbreviata(DC.) Newman; ~ D. filix-mas.

Sporophyte. The rhizomes short, stout; more or less erect; bearing scales (densely scaly, with broad, soft scales). Plants with no clear distinction into fertile and sterile leaves.

Leaves aggregated terminally (crowns several); to 30–50(–120) cm long; usually dying in the autumn; compound; complexly divided; once pinnate, with conspicuously divided pinnae (the pinnules with teeth spreading fan-wise at the apex). Pinnae 20–35 on each side of the leaf. The petioles shorter than the blades (densely at the base and sparsely or moderately above covered with uniformly pale brown scales, the larger of these ovate-lanceolate); about 0.1–0.25 x the length of the blade (about 1/8–1/4 as long); vascularised by several discrete strands (derived via several leaf traces). Petiolar scales not golden brown (dull pale brown, rather numerous). The longest pinnae around the middle of the blade (the pinnae decreasing markedly in length basipetally, the lowest pinna less than half the length of the longest); 5–15 cm long. The pinnae decreasing markedly in length towards the base of the blade, the basal ones relatively short. The bases of the pinnae without a dark blotch at the base. The venation of the lamina open.

The sporangia superficial; protected; aggregated in sori. The sori sub-orbicular (rather large, borne on each side of the midrib of the largest pinnules); remaining discrete at maturity; 2–4 on either side of the mid-rib of the larger pinnules (not more than two, and often only 1, on the majority of them); with a true indusium. The indusia reniform and attached at the indentation; entire, with minute glands on the margin.

Distribution and habitat. Rocky, open or lightly shaded places on mountains, scree slopes, mostly above 240 m. Wales, northern England south to mid-west Yorkshire, Scotland, and Ireland in Kerry and County Down.

Vice-county records. Britain: South Hampshire, Herefordshire, Shropshire, Glamorgan, Breconshire, Radnorshire, Carmarthenshire, Cardiganshire, Montgomeryshire, Merionethshire, Caernarvonshire, Denbighshire, Derbyshire, Cheshire, South Lancashire, West Lancashire, Mid-west Yorkshire, North-west Yorkshire, Durham, South Northumberland, North Northumberland, Westmorland, Cumberland, Dumfriesshire, Kirkcudbrightshire, Wigtownshire, Ayrshire, Lanarkshire, Peeblesshire, Selkirkshire, Roxburghshire, Midlothian, Stirlingshire, West Perthshire, Mid Perthshire, East Perthshire, Angus, Kincardineshire, South Aberdeenshire, Banffshire, 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. Ireland: South Kerry, North Kerry, West Donegal, Down, Antrim.

Classification. Family Polypodiaceae (C.T.W.); Dryopteridaceae (Swale and Hassler); Dryopteridaceae (Stace). Order Dryopteridales (Swale and Hassler).

D. x mantoniae Fraser-Jenk., & Corley = D. oreades x D. filix-mas; D. x pseudoabbreviata Jermy = D. oreades x D. aemula.

Illustrations. • 9 other 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.’.