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

29. Polystichum yigongense Ching & S. K. Wu, Fl. Xizang. 1: 210. 1983.

易贡耳蕨 yi gong er jue

Plants evergreen. Rhizome erect, densely covered with broadly lanceolate brown or reddish brown scales; scales up to 1.5 × ca. 0.7 cm. Fronds up to 50 cm; stipe stramineous, ca. 15 cm, 4-6 mm in diam. at base, densely covered with broadly lanceolate scales; scales brown or reddish brown, apex twisted. Lamina bipinnate, lanceolate, ca. 37 × 9 cm, base rounded, slightly contracted, apex acuminate; rachis without proliferous bulbils, abaxially densely scaly; scales brown, lanceolate and linear-lanceolate, often strongly twisted. Pinnae ca. 25 pairs, alternate, spreading, approximate, lanceolate, middle pairs ca. 4.5 × 1.5 cm, obliquely broadly cuneate, shortly stalked, pinnate, acute. Pinnules 8-10 pairs, alternate, ascendant, approximate, rhombic, bases obliquely cuneate, margins entire or with few small forward-pointing acute teeth, apices acuminate and spinulose; basal acroscopic pinnules largest; abaxially scaly; microscales filiform, strongly ciliate at base; frond texture leathery; venation pinnate on pinnules, concave abaxially, flat or slightly concave adaxially. Sori in 1 row on each side of midrib; indusia present, entire.

● Stone crevices; ca. 2400 m. Xizang (Yigong).

Polystichum yigongense, which was not recognized in FRPS (5(2): 49. 2001), is distinguished by its rhombic pinnules with short, sharp teeth as opposed to the nearly elliptic pinnules with long, sharp teeth in P. neolobatum. The two species have remarkably different spore sculptures.

Polystichum yigongense was treated as a synonym of P. makinoi (Indian Fern. J. 2: 9. 1985) and P. neolobatum (Himalayan Ferns (Guide to Polystichum), 27. 1997) by Fraser-Jenkins.


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