British ferns (Filicopsida)
Cystopteris fragilis subsp. dickieana (Sim) Hylander.
Sporophyte. The rhizomes rather stout; more or less decumbent; bearing scales (these thin, brown, lanceolate). Plants with no clear distinction into fertile and sterile leaves.
Leaves aggregated terminally; to 5–20(–35) cm long; dying in the autumn; circinnate; compound; complexly divided; bipinnate with more or less undivided pinnules. Pinnae 5–15 on each side of the leaf (? - up to 15). The leaves not as in Pteris (q.v.). The petioles shorter than the blades to about as long as the blades (from a third as long, slender and brittle, dark brown at the base and paler above, with a few scales at the base and usually a few hair-like scales above). Leaf blades in outline lanceolate. The longest pinnae about a third of the distance from the base of the blade to around the middle of the blade; 1–4 cm long. The adjacent pinnae strongly overlapping. The venation of the lamina open.
The sporangia superficial; protected; aggregated in sori. The sori sub-orbicular (small, each on a receptacle with a vascular strand from the vein, with a row of several borne on either side of the midrib of the pinnule); 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. The mature spores rugose; without a perispore.
Distribution and habitat. On base-rich substrates. Associated with basic rocks in maritime caves and stream-gorges. Kincardines, Easterness and mid-Perthshire.
Vice-county records. Britain: Mid Perthshire, East Perthshire, Kincardineshire, South Aberdeenshire, Banffshire, East Inverness-shire.
Classification. Family Polypodiaceae (C.T.W.); Cystopteridaceae (Swale and Hassler); Woodsiaceae (Stace). Order Athyriales (Swale and Hassler).
Illustrations. • C. dickieana: as C. alpina var. dickieana, Eng. Bot. 1867 (1886). • C. dickieana: Sowerby and Johnson (1859). • Cystopteris species (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’.