Arachniodes simplicior (Makino) Ohwi

East Indian holly fern

Etymology Simplicior means simpler, referring to being simpler than A. aristata, of which it was considered to have been a variety.
Description Rhizome: long creeping, 5--8 mm diam., densely scaly, knotty.
Frond: 80 cm high by 20 cm wide, evergreen, monomorphic, but the fertile fronds are taller, narrower, blade/stipe ratio: 3:2.
Stipe: light green to dark at the base, spaced 0.5--4 cm apart, old stipes persistent, scales lanceolate, tan, vascular bundles: "4 or more in an arc" but only three are seen in the photo below.
Blade: 2-pinnate, but sometimes said to be more divided because of the downward-pointing pinnule of the lowest pinna, deltate or pentagonal, papery, dark green, lustrous above, pale below, below: hairlike scales.
Pinnae: 12 to 20 pair, after 3 or 4 pair, the remaining pinnae are very much reduced to a 1-pinnate series; pinnules large closest to the rachis (compared to the remainder) the downward-pointing one very large; costae grooved above, continuous from rachis to costae to costules; segments undivided to pinnatifid, somewhat imbricate (overlapping); margins shallowly dentate, finely spiny; veins free, forked, prominent on the lower surface.
Sori: round, between midrib and margin, indusium: reniform, attached at a sinus, sporangia: translucent.
Dimensionality: the blade is more or less held horizontally above a stipe that varies from vertical to 45.
Culture Habitat: rather dry mountain forests, often at foot of cliffs. Distribution: Japan and China. Hardy to -15C, USDA Zone 7.
Distinctive Characteristics In North America the only form in commerce is the selection 'Variegata' with a light yellow-green band near the costae, or on smaller fronds, near the rachis.
Aspidium aristatum (G. Forster) Swartz var. simplicius Makino
Byrsopteris simplicior (Makino) Kurata
Polystichopsis simplicior (Makino) Tagawa
Rumohra simplicior (Makino) Ching
Arachniodes simplicior
Arachniodes simplicior 'Variegata'. Habit: note nearly horizontal fronds, three large pinnae pair, the lowest with one pinnate, downward-pointing pinnule, and a shrunken apex pinnate in form. Click for more detail.  Photo: Tom Stuart
Nomenclature Often known in the trade as A. aristata, which it resembles. A. simplicior is usually less divided, but this varies, and an easier difference is seen in the abrupt reduction to smaller pinnae, here after only 3-4 larger ones. In A. aristata there are 5 or more large pinnae pairs prior to the abrupt reduction, though young plants may also confuse the observer.
Sorus The text at Flora of North America indicates 1 mm for the size of the sorus, but an accompanying illustration there (see sorus photo above) shows about 2 mm. Someone with the facts please report.
Arachniodes simplicior vascular bundles
Arachniodes simplicior. Scan of stipe at base. The description given for the genus in FNA, "vascular bundles more than 3, arranged in an arc, round in cross section," is not borne out here.  Photo: Tom Stuart
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