Oreopteris limbosperma (Allioni) Holub

Sweet mountain fern, Lemon-scented fern

Etymology Limbo = marginal, spermum = seed; marginal seed/sori; the first name was Polypodium limbospermum assigned in 1789 when sori were not regarded so distinctly from seeds.
Description Rhizome: erect, branching, triangular scales.
Frond: 120 cm high by 20 cm wide, deciduous, monomorphic or somewhat dimorphic, blade/stipe ratio: 5:1.
Stipe: grooved above (not continuous) or not, scales thin, silvery early, later pale buff, continuing onto the rachis, vascular bundles: 2, crescent-shaped.
Blade: 1-pinnate-pinnatifid, ovate, tapering at the base to widely-spaced, very short pinnae, soft, yellow-green early, pale green later, transparent needlelike hairs on the costae, yellow glands on the lower surface.
Pinnae: 30 to 40 pair, pinnatifid above, lowest ones losing this character; costae grooved above, grooves discontinuous from rachis to costae; margins entire to shallowly crenate, fertile segments inrolled; veins free.
Sori: round, touching at maturity, more plentiful on the upper portion of the frond, near the margins, indusium: absent (to the eye), sporangia: pale green early, later black, glossy, maturity: mid to late summer.
Culture Habitat: moist, acidic, shady woods, banks. Distribution: widely scattered in Europe, from the Azores to Norway to Turkey. Hardy to -25°C, USDA Zone 5.
Distinctive Characteristics lemon scent when the glands on the lower surface are brushed; inrolled fertile margins
Synonyms
Polypodium limbospermum All.
Dryopteris montana O. Kuntze
Thelypteris limbosperma (Allioni) H.P. Fuchs
Thelypteris oreopteris (Ehrh.) Slosson
Dryopteris oreopteris (Ehrh.) Maxon
Aspidium montanum Aschers.
Lastrea oreopteris Bory
Oreopteris limbosperma
Oreopteris limbosperma. upper left: juvenile sporophyte and gametophytes, lower left: pinna base and sori, right: scales from rhizome and stipe  Illustration from Scandinavian Ferns by Benjamin Øllgaard and Kirsten Tind, Rhodos, 1993.
Notes
Taxonomy Thelypteris quelpaertensis (or Oreopteris quelpaertensis), of northeastern Asia, northwestern North America and disjunct in Newfoundland, is very similar and was earlier called (by either genus) limbosperma. It is omitted here as believed not to be in cultivation.
Oreopteris limbosperma
Oreopteris limbosperma. Habit, growing with Vaccinium uliginosum, Cornus suecica, and Deschamsia flexuosa.  Illustration from Scandinavian Ferns by Benjamin Øllgaard and Kirsten Tind, Rhodos, 1993.
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