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Published In: Familles des Plantes 2: 20. 1763. (Fam. Pl.) Name publication detailView in BotanicusView in Biodiversity Heritage Library
 

Project Name Data (Last Modified On 7/9/2009)
Acceptance : Accepted
Project Data     (Last Modified On 8/5/2009)

 

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5. Dryopteris Adans. (shield fern, wood fern)

Rhizomes erect to prostrate and short-creeping, scaly. Leaves monomorphic to slightly dimorphic. Petioles straw-colored, shorter than the leaf blade, scaly, the bases with 4–9 vascular bundles. Rachises glabrous or scaly, lacking stalked glands. Leaf blades lanceolate to deltoid or ovate in outline, less commonly obovate, 1–3 times pinnately compound, the pinnules toothed, often deeply lobed. Veins not anastomosing. Sori circular or nearly so. Indusia kidney-shaped to circular-cordate, attached at the base of the notch. Spores 64 per sporangium, monolete, 38–64 mm long, brown. About 225 species, nearly worldwide, but most diverse in Asia.

The North American species of Dryopteris form a large complex involving past hybridization and polyploidy. The hybrid origin of most of the fertile polyploids can make determinations in the genus difficult in some cases. Elsewhere, numerous sterile hybrids have been described; however, none of these has been reported from Missouri to date. The taxa present in the state are sufficiently uncommon that there is little chance of hybridization between them. However, a few of the most likely hybrids potentially to occur in Missouri are listed below under their parental species. Students of the flora should be aware that anywhere that two or more species of Dryopteris grow together the potential for sterile hybrids exists.

Among the Missouri species, most are deciduous. However, the leaves of D. marginalis are evergreen, and those of D. intermedia tend to overwinter but often partially turn brown and shrivel.

 

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1 Leaves leathery; sori near the pinna margins, the indusia thick, not shriveling at maturity 6 Dryopteris marginalis
+ Leaves herbaceous to papery; sori near the midribs or halfway between the margins and midribs, the indusia thin, shriveling at maturity (2)
2 (1) Leaf blades narrowly lanceolate to narrowly oblong in outline, the pinnae of fertile leaves often twisted like venetian blinds at right angles to the plane of the leaf 3 Dryopteris cristata
+ Leaf blades deltoid to ovate, obovate, or lanceolate in outline, flat (3)
3 (2) Leaf blades pinnately compound above to sometimes 2 times pinnately compound below, the pinnules mostly deeply lobed; rhizome and petiole scales dark brown, sometimes with lighter margins, shiny (4)
+ Leaf blades 2 times pinnately compound above to often 3 times pinnately compound below, the pinnules mostly deeply lobed; rhizome and petiole scales tan, concolorous, not shiny (5)
4 (3) Leaf blades ovate-lanceolate, tapering gradually to the tip and broadest at or below the middle; sori about halfway between the midribs and margins of the pinnules or pinnule lobes 2 Dryopteris celsa
+ Leaf blades elliptic to somewhat obovate, tapering abruptly to the tip and broadest at or above the middle; sori usually closer to the midribs than to the margins of the pinnules or pinnule lobes 4 Dryopteris goldiana
5 (3) Basal lower segment of basal pinnae 2 or 3 times longer than the basal upper segment, and longer than the adjacent basal segment; leaf blades and indusia glabrous 1 Dryopteris carthusiana
+ Basal lower segment of basal pinnae 1 or 2 times as long as the basal upper segment and as long as or shorter than the adjacent basal segment; leaf blades often with tiny glands on the rachis and midribs, and most notably the indusia 5 Dryopteris intermedia
 
 
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