独龙江双盖蕨 du long jiang shuang gai jue

Basionym: Allantodia dulongjiangensis W. M. Chu, Acta Bot. Yunnan., Suppl. 5: 38. 1992.

Plants evergreen, medium-sized to large. Rhizome erect, dark brown, up to 3 cm in diam., apex with sparse adpressed scales; fronds caespitose. Fertile fronds up to 1.6 m; stipe dark black at base, upper part (and rachis) light brown or dark stramineous, up to 70 cm, up to 1 cm in diam., with dense scales and light brown, adpressed, uniseriate, thin, nodose hairs when young, then scales and hairs mostly deciduous; scales brown or chestnut-black, shiny, lanceolate or ovate-lanceolate, base deeply cordate, contiguous, attached to stipe and rachis with variably long stalk or stalkless, margin sparsely serrate or irregularly toothed, apex acuminate or abruptly narrowed and caudate; scale stalks dark brown, flat-linear, upper stalks gradually narrowed, mostly persistent, bristlelike after scales deciduous, irregularly adpressed; lamina 2-pinnate with pinnatilobate to pinnatisect pinnules, deltoid, up to 90 × 70 cm, apex acuminate; pinnae up to 18 pairs, alternate, slightly ascending, apex acuminate; lower pinnae broadly oblong-lanceolate, up to 50 × 17 cm, with stalk up to 5 cm; upper pinnae reduced, shortly stalked to sessile, broadly lanceolate to lanceolate, uppermost pinnae only ca. 3 cm × 5 mm; pinnules 15 pairs, alternate, spreading or slightly ascending, lanceolate, oblong-lanceolate, or narrowly ovate, up to 10 × 2 cm, base shallowly cordate or broadly cuneate, usually asymmetrical (basal acroscopic lobe slightly narrow), shortly stalked or sessile, pinnatipartite to pinnatisect, apex acuminate or shortly acuminate to acute, sometimes subrounded; pinnule lobes often ca. 10 pairs, sometimes 15 pairs, subspreading, oblong or subrectangular, slightly falcate, margin sparsely shallowly serrate, apex rounded-cuneate; 1 basal basiscopic lobe usually pinnatilobate; veins pinnate, not prominent adaxially, slightly visible adaxially, veinlets ascending, mostly forked, up to 6 pairs per lobe. Lamina herbaceous, rachis and lower part of costa light brown when dry, upper part of costa stramineous; pinnules light brown, glabrous adaxially; both surfaces of rachis and adaxial surface of costa with sparse scales similar to those on stipe, but stalked scales few; costule abaxially with sparse ovate or broadly ovate-lanceolate, brown or chestnut, shiny, deeply cordate, marginally sparsely irregularly toothed, membranous scales, veins abaxially usually with light brown, thin, nodose hairs. Sori oblong, up to 6 pairs per lobe, densely contiguous, mostly single, basal acroscopic sori double; indusia light brown, entire, membranous, vaulted, opening acroscopically. Spores subreniform, perispore hyaline, projections few, rugate.

● Evergreen broad-leaved forests; 1400-2000 m. NW Yunnan (Gongshan).

Diplazium dulongjiangense is one of two species of Diplazium with stalked scales; it differs from the similarly scaled D. kawakamii in the rhizome erect, stipe and rachis often light brown, lamina with thin pale brown nodose hairs and remaining scales irregularly adpressed, and sori densely contiguous when mature.