British ferns (Filicopsida)
European Chain Fern.
Sporophyte. The rhizomes bearing scales. Plants with no clear distinction into fertile and sterile leaves.
Leaves aggregated terminally; rooting at their tips from a scaly bud; to 30–200 cm long; persistent; compound; complexly divided; once pinnate, with conspicuously divided pinnae (approaching bipinnate, the pinnae being deeply and acutely lobed). Pinnae numerous. The petioles shorter than the blades (not more than a third as long as the blade and often much less); vascularised by several discrete strands. Leaf blades in outline ovate-triangular, or lanceolate, or lanceolate-triangular; somewhat leathery. The longest pinnae near the base of the blade. The adjacent pinnae distant from one another and not at all overlapping. The venation of the lamina mostly open.
The sporangia marginal to superficial; aggregated in sori. The sori stout, in a row on either side of the pinna-lobe midribs; remaining discrete at maturity; with a true indusium (this the same shape as the sorus, opening towards the mid-rib). The mature spores monolete; without a perispore.
Distribution and habitat. A mainland-european species, perhaps naturalized. Regenerates in gardens in S. Kerry and W. Cornwall.
Vice-county records. Britain: West Cornwall, Isle of Wight, Channel Islands. Ireland: South Kerry.
Classification. Family Polypodiaceae (C.T.W.); Blechnaceae (Swale and Hassler); Blechnaceae (Stace). Order Athyriales (Swale and Hassler).
Illustrations. • Woodwardia radicans (photo).
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’.