棕鳞双盖蕨 zong lin shuang gai jue

Allantodia forrestii Ching ex Z. R. Wang, Acta Phytotax. Sin. 32: 82. 1994; A. subintegra Ching & Y. X. Lin.

Plants evergreen, large. Rhizome ascending, black-brown, up to 5 cm in diam., apex scaly; scales dense, loose, yellow-brown, slightly shiny, lanceolate or linear-lanceolate, 1-1.5 cm, margin minutely toothed; fronds caespitose. Fertile frond up to 2 m; stipe black-brown at base, upward yellow-brown, up to 1 m, up to 8 mm in diam., base densely scaly, scales similar to those on rhizome, upward sparsely scaly; scales yellow-brown, linear-lanceolate to linear; lamina 2-pinnate, broadly ovate-deltoid or deltoid, up to 1 m × 90 cm; pinnae up to 14 pairs, alternate, ascending; lower pinnae oblong-lanceolate or broadly lanceolate, up to 50 × 25 cm, with stalk up to 3 cm, apex acuminate, distal part shallowly incised; upper pinnae gradually shortened, lanceolate, pinnatilobate or entire, similar to and as large as pinnules of lower pinnae; pinnules up to 13 pairs, alternate, subspreading, oblong-lanceolate, up to 12 × 2.5 cm, base shallowly cordate, rounded, or subtruncate, mostly shortly stalked, lobed to rounded-lobed, or incised, apex acuminate or long acuminate, in small plants margin subentire; veins pinnate, veinlets less than 5 pairs, simple, ascending, basal veinlets curved. Lamina thickly papery when dry, green, lighter abaxially; rachis and costae abaxially with sparse linear, yellow-brown scales, costules and midribs abaxially with thin, yellow-brown, membranous scales. Sori linear, 1-6 on either side of midrib, mostly double, from midrib to 2/3 of veinlet length; indusia yellow-brown, membranous, margin entire when young, then gradually erose or lacerate. Spores subreniform, perispore hyaline and prominent, few rugate.

Evergreen broad-leaved forests; 1400-2100 m. ?Taiwan, SE Xizang (Mêdog), NW and W Yunnan (Fugong, Gongshan, Tengchong) [NE India, N Myanmar].

Diplazium forrestii is similar to D. dilatatum but differs by the scales yellow-brown, stipe and rachis densely scaly, pinnules incised or subentire, and sori mostly double, linear from midrib to below margin. It is also similar to D. glingense (the type of each from Mêdog) but differs by the scale color.

For further views on Diplazium forrestii, see Fraser-Jenkins (loc. cit.: 256-258) and Knapp (Ferns Fern Allies Taiwan, 449-450. 2011).