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FOC | Family List | FOC Vol. 2-3 | Dryopteridaceae | Polystichum

180. Polystichum pseudodeltodon Tagawa, Acta Phytotax. Geobot. 6: 159. 1937.

拟对生耳蕨 ni dui sheng er jue

Polystichum deltodon (Baker) Diels var. pseudodeltodon (Tagawa) Tagawa.

Plants evergreen. Rhizome ascending to erect, short, 1-2 cm in diam. including stipe bases, rhizome apex and basal stipe densely scaly; scales brown to dark brown, ovate or ovate-lanceolate, up to 6 × 2 mm, thickly membranous, subentire, acuminate. Fronds 27-57 cm; stipe stramineous, 10-20 cm, 0.5-1.5 mm in diam., upper stipe base sparsely scaly; scales brown to dark brown, ovate-lanceolate or lanceolate, varying in size, membranous, margins with a few long teeth, apices caudate or long acuminate, evanescent; remnant scales often appressed. Lamina light green or light brownish green when dry, lanceolate or narrowly elliptic-lanceolate, 17-37 × 2-4 cm at middle, base slightly contracted or not, 1-pinnate, apex pinnatifid and acuminate; rachis stramineous, without proliferous bulbils, sparsely scaly on both surfaces; scales brown to pale dark brown, ovate, membranous, with a few long teeth, caudate. Pinnae 18-38 pairs, often alternate, rarely nearly opposite, approximate, lower pairs obviously approximate, often nearly spreading, sometimes upper pairs slightly ascendant, sometimes most pinnae or those below middle of lamina slightly angled basiscopically, oblong, middle pairs 11-21 × 4-8 mm at base, apices slightly curved upward, rounded and shortly spinulose, bases asymmetrical, acroscopic base auriculate, auricles deltoid or nearly deltoid, apex of auricles acute or acuminate and shortly spinulose, proximal margins of auricles truncate or slightly curved, entire or with 1 or 2 shallow obtuse teeth, parallel to rachis or slightly overlapping rachis, distal margins of auricles often with 1 or 2 shallow incised rounded teeth or shallowly spinulose or sometimes acute coarse teeth, acroscopic margins of pinnae truncate or slightly recurved and coarsely toothed or biserrate, basal basiscopic margins narrowly cuneate, straight, margins entire, distal basiscopic margins curved upward, with coarse and often shortly spinulose teeth; adaxially glabrous, abaxially sparsely covered with narrowly lanceolate light brown microscales; frond texture thickly papery; venation slightly distinct abaxially, distinct adaxially, pinnate; lateral veins pinnate above midrib from base to apex, dichotomous or simple, simple or dichotomous below midrib, sterile veinlets reaching tooth base. Sori small, terminal on veinlets, close to pinna margin, often 1 row above midrib, up to 10, only 1-3 below midrib on apical part or sterile; indusia present, brown, erose, caducous.

● Grassy slopes in forests; 700-2300 m. Taiwan.

Polystichum pseudodeltodon is often synonymized with P. deltodon, but the former has rounded pinna apex, while the latter has acute pinna apex. Preliminary molecular analysis confirmed their separation into two species (Zhang et al., unpublished data).


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