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Ferns (Filicopsida) of Britain and Ireland

L. Watson and M.J. Dallwitz

Cystopteris montana (Lam.) Desv.

“Mountain Bladder-fern”.

Sporophyte. The rhizomes long and slender; long and rather creeping (about 2 mm in diameter, blackish); bearing scales (when young, these few, scattered, ovate).

Leaves distributed along the rhizomes (distant); to 10–30(–45) cm long; dying in the autumn; circinnate; complexly divided; bipinnate with conspicuously divided pinnules to tripinnate with undivided ultimate pinnules. Pinnae 4–13 on each side of the leaf (? - “up to 13”). The petioles longer than the blades (with a few ovate-lanceolate scales mainly near the base, dark brown at the base and paler above). Leaf blades in outline ovate-triangular. The longest pinnae the lowermost; 2.5–7 cm long. The adjacent pinnae approximated but not strongly overlapping to distant from one another and not at all overlapping. The venation of the lamina open.

The sporangia superficial; protected; aggregated in sori. The sori sub-orbicular (each on a receptacle with a vascular strand from the vein, widely separated, borne singly or in two short rows, one on either side of the midrib of ultimate segments); remaining discrete at maturity; with a true indusium. The indusia not reniform but flap-like from the base of the sorus, vaulted at first, later reflexed; whitish, ovate-orbicular, acute or sub-obtuse, irregularly toothed. The mature spores without a perispore.

Distribution and habitat. On base-rich substrates. Shady, wet, basic rock ledges, gullies and scree above 700 m. Local in central Scotland, formerly in Westmoreland.

Vice-county records. Britain: Westmorland, Stirlingshire, Mid Perthshire, East Perthshire, Angus, South Aberdeenshire, East Inverness-shire, West Inverness-shire, Argyll Main, South Ebudes.

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

Illustrations. • C. montana: Eng. Bot. 1868 (1886). • C. montana: Sowerby and Johnson (1859). • Cystopteris species (inter alia). Thelypteridaceae. 1721, Oreopteris limbosperma. Dryopteridaceae. 1722, Dryopteris filix-mas; 1723, Dryopteris submontana; 1724, Dryopteris cristata; 1725, Dryopteris carthusiana; 1726, Dryopteris dilatata; 1727, Dryopteris aemula. 1728, Polystichum lonchitis; 1729 and 1730, Polystichum aculeatum; 1731, Polystichum setiferum. CYSTOPTERIDACEAE. 1732, Cystopteris fragilis; 1733, C. fragilis var. angustata; 1734, C. fragilis var. dentata; 1735, Cystopteris alpina; 1736, Cystopteris montana; 1737, Cystopteris dickieana. Athyriaceae. 1738, Athyrium filis-femina. Aspleniaceae. Asplenium fontanum; 1740, Asplenium obovatum subsp. lanceolatum. From Sowerby and Johnson (1863, the family assignments following Swale and Hassler).


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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’.

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