Dryopteris intermedia
Dryopteris clintoniana
dryoptère spinuleuse, evergreen wood fern, fancy fern, intermediate woodfern
Clinton's wood fern, dryoptère de Clinton
monomorphic, green through winter, 32–90 × 10–20 cm.
dimorphic, 45–100 × 12–20 cm;
fertile leaves dying back in winter;
sterile leaves 1–several, smaller, green through winter.
1/3 length of leaf, scaly at least at base;
scales scattered, tan.
1/4–1/3 length of leaf, scaly at least at base;
scales scattered, tan, sometimes with dark brown center.
green, ovate, 3-pinnate-pinnatifid, herbaceous, glandular.
green, lanceolate, with nearly parallel sides, pinnate-pinnatifid, herbaceous, not glandular.
± in plane of blade, lanceolate-oblong;
basal pinnae lanceolate, not reduced, basal pinnules longer than adjacent pinnules, basal basiscopic pinnule longer than basal acroscopic pinnule;
pinnule margins serrate, teeth spiny.
of fertile leaves twisted out of plane of blade but not fully perpendicular to it, narrowly elongate-deltate;
basal pinnae narrowly elongate-deltate, much reduced;
basal pinnules longer than or equal to adjacent pinnules, basal basiscopic pinnule and basal acroscopic pinnule equal;
pinnule margins serrate or biserrate, with spiny teeth.
with minute glandular hairs.
lacking glands.
midway between midvein and margin of segments.
midway between midvein and margin of segments.
= 82.
= 246.
Dryopteris intermedia
Dryopteris clintoniana
A related taxon, Dryopteris intermedia subsp. maderensis (J. Milde ex Alston) Fraser-Jenkins, occurs on eastern Atlantic islands.
Dryopteris intermedia and the other taxa in the " D. spinulosa complex" have long confounded taxonomists. Dryopteris intermedia is diploid and is one of the parents of the allotetraploids D. carthusiana and D. campyloptera. Dryopteris intermedia hybridizes with eight species. All hybrids are easily detected by the distinctive glandular hairs on the indusia and, usually, on the costae and costules.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Dryopteris clintoniana is a North American endemic and an allohexaploid derived from D. cristata and D. goldieana. Dryopteris clintoniana hybridizes with six species. Hybrids can be identified by the fairly narrow blades and elongate-deltate proximal pinnae.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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