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

204. Polystichum elevatovenusum Ching ex W. M. Chu & Z. R. He, Fl. Reipubl. Popularis Sin. 5(2): 226. 2001.

凸脉耳蕨 tu mai er jue

Plants evergreen. Rhizome ascending or erect, short, 2-2.5 cm including stipe bases, rhizome apex densely scaly; scales brown, lanceolate, up to 8 × 1 mm, thickly membranous, subentire. Fronds few per rhizome, 45-70 cm; stipe stramineous, 12-20 cm, 1.5-2 mm in diam., base densely scaly; scales similar to rhizome scales or wider, slightly spreading, distal stipe with similar but appressed membranous brown scales. Lamina 1-pinnate, both surfaces grayish green when dry, adaxially slightly shiny, narrowly elliptic-lanceolate, 33-50 × 3.5-6 cm at middle, slightly contracted toward base from middle, 2-4 cm wide at base, apex acuminate; rachis stramineous, without proliferous bulbils, abaxially sparsely scaly; scales similar to stipe scales but smaller, appressed, thin. Pinnae 30-45 pairs, alternate or nearly opposite, upper pairs contiguous to imbricate, often attached at right angles with rachis, lower pairs or only basalmost pairs ± reflexed, falcate or oblong, apices slightly angled acroscopically, acute, bases obviously asymmetrical, acroscopic base with deltoid auricles with acute tips, proximal margins of auricles truncate or slightly curved, parallel to rachis, basal basiscopic margins narrowly cuneate, straight or substraight, margins entire, distal part of basiscopic margins curved upward, both margins with shallow obtuse teeth or with incised shallow rounded teeth; adaxially glabrous, abaxially sparsely scaly; microscales light brown, lanceolate, small; frond texture thinly leathery; venation pinnate, obviously raised abaxially, distinct adaxially; lateral veins often dichotomous, rarely simple, pinnate on auricles, nearly reaching pinna margin. Sori small, in 1 row on each side of midrib, more above midrib, terminal on shorter veinlets, close to pinna margins; indusia present, brown, caducous.

● Wet limestone crevices, red soils derived from limestone, in forests or under bushes; 1200-2400 m. NW, S, and W Yunnan.

Polystichum elevatovenusum is similar to P. acutidens, but its lamina texture is thicker, i.e., thickly papery, its pinna margins have rounded, non-spinulose teeth, its veins are obviously raised abaxially, and its sori are close to the pinna margin.


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