Athyrium niponicum (Mett.) Hance

Japanese painted fern

Etymology Niponicum is the Latinized word for Nippon or Japan.
Description Rhizome: long-creeping, about 3 mm diam., also listed as short-creeping, scaly.
Frond: 70 cm high by 25 cm wide, deciduous, monomorphic, blade/stipe ratio: 1:1 or a little more.
Stipe: straw-colored, or sometimes red-purple, scales lanceolate, 4--6 mm long, 1 mm broad, membranous, entire at margin, pale brown, falling early, vascular bundles: 2, peanut-shaped, at stipe base, uniting to a u- or v--shape above.
Blade: 2-pinnate pinnatifid, abruptly narrowed toward terminal pinna-like apex, lanceolate, the uppermost pinnae sessile, sharply reduced, herbaceous, soft, scales on rachis lanceolate, sparse.
Pinnae: 10 to 20 pair, opposite to alternate, anadromous at base of blade, becoming isodromous above, long-stalked, lanceolate, long-tapering; pinnules lanceolate, obtuse to pointed at apex, 1--3 cm long, 3--15 mm broad, longest below the middle of the pinna; costae grooved above, continuous from rachis to costae to costules; margins serrate to deeply pinnatifid; veins free, not reaching the margin, not easy to see without a lens.
Sori: varying in shape, in a basic herringbone pattern, merging at maturity, medial, between midrib and margin, indusium: shape as for sori, whitish, shriveling, attached along the vein, sporangia: dark brown, maturity: summer.
Dimensionality: lowest pinnae bending forward, above the plane of the blade.
Culture Habitat: lowlands, shade. Distribution: China, Japan, Korea, Manchuria. Hardy to -35C, USDA Zone 3.
Distinctive Characteristics Most plants in commerce are the selection 'Pictum', not really a selection, but a whole range of variations on silver and maroon shadings to the costae and lamina.
Synonyms
Asplenium niponicum Mett.
Asplenium uropteron Miq.
Athyrium uropteron (Miq.) C. Chr.
Athyrium goeringianum (Kunze) Moore
Athyrium niponicum
Athyrium niponicum. Pinna upper surface with coloration extending well up the costa; grooves visible on the enlarged version.  Scan: Tom Stuart
Athyrium niponicum
Athyrium niponicum. Two peanut-shaped vascular bundles at stipe base merging upwards to an open v-shape.  Scan: Tom Stuart
Athyrium niponicum
Athyrium niponicum. Immature and mature pinnules showing all the typical athyroid shapes: lunate, inverted-j, and hooked. At maturity all merge.  Scan: Tom Stuart
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