墨脱双盖蕨 mo tuo shuang gai jue

Allantodia medogensis Ching & S. K. Wu, Fl. Xizang. 1: 150. 1983.

Plants evergreen, medium-sized. Rhizome usually ascending to erect, sometimes creeping, erect, up to 20 cm tall, ca. 4 cm in diam.; fronds caespitose. Fertile fronds up to 60 cm; stipe black-brown at base, upward light brown, up to 1 cm in diam. at base, with sparse dark brown, ovate, adpressed scales, upward glabrous or slightly rough, occasionally scaly; lamina 2-pinnate, pinnules pinnatipartite to pinnatisect, or nearly 3-pinnate, deltoid, up to 85 × 85 cm, apex acuminate; pinnae up to 15 pairs, alternate or basal pinnae subopposite, slightly ascending, stalked, apex acuminate; lower pinnae deltoid or broadly oblong-lanceolate, up to 45 × 20 cm, with stalk up to 5 cm, often nearly 2-pinnate; upper pinnae gradually shorter, lanceolate; pinnules up to 15 pairs, alternate, broadly oblong-lanceolate or lanceolate, up to 15 × 5 cm, lower pinnules shortly stalked, upper pinnules sessile, base broadly cuneate or subtruncate, pinnatipartite to pinnatisect, sometimes base with 1 pair of free pinnule lobes, apex acuminate; costa prominently broadly grooved adaxially; pinnule lobes up to 15 pairs or more, subspreading, narrowly oblong, up to 3 × 1 cm, margin usually dentate, sometimes subentire or shallowly pinnatilobate, apex rounded or subtruncate, rarely acute; one basal acroscopic lobe usually smaller; veins pinnate, veinlets forked or pinnate. Lamina thickly papery when dry, light brown-green, dark on adaxial surface, glabrous on both surfaces; rachis and costa light brown or light stramineous. Sori often 3-6 pairs per lobe, oblong, close to midrib; indusia brown, membranous, vaulted, irregularly ruptured when mature. Spores reniform, perispore prominent and hyaline, wide, not rugate, with some granular projections.

● Evergreen broad-leaved forests; 1300-1900 m. Xizang, Yunnan.

Diplazium medogense is similar to D. spectabile but differs by the rhizome erect, stipe and rachis yellow-brown when dry, pinnules up to 15 × 5 cm, pinnule lobes sickle-shaped oblong, serrate at margin, not pinnatilobate, and sori not contiguous when mature.