67. Diplazium laxifrons Rosenstock, Hedwigia. 56: 337. 1915.
异裂双盖蕨 yi lie shuang gai jue
Allantodia laxifrons (Rosenstock) Ching; A. inaequiloba Ching; Diplazium polypodioides Blume var. sinense Christ.
Plants evergreen, medium-sized to large. Rhizome creeping or ascending to erect, sometimes trunk up to 40 cm tall, ca. 10 cm in diam., apex slightly scaly; scales brown and thin, adpressed; fronds approximate to caespitose. Fertile frond up to 2.5 m; stipe dark brown at base, upward brown or green-stramineous, up to 1 m, up to 1 cm in diam., glabrous, shallowly grooved adaxially; lamina 2-pinnate with pinnules pinnatilobate to pinnatipartite, deltoid or ovate-deltoid, up to 1.5 × 1 m, apex acuminate; pinnae up to 20 pairs, alternate, ascending; lower pinnae broadly oblong-lanceolate or broadly lanceolate, symmetrical, up to 60 × 20 cm, with stalk up to 6 cm, base black-brown, apex acuminate; upper pinnae lanceolate, slightly asymmetrical (basiscopic lobe longer), base sessile or subsessile, pinnatifid to pinnatipartite, apex acuminate; pinnules up to 20 pairs, alternate, spreading, lanceolate, up to 13 × 3 cm, base shallowly cordate, truncate, or broadly cuneate, asymmetrical, acroscopic lobe prominent, pinnatipartite or subpinnatisect, apex acuminate or long acuminate; pinnule lobes more than 15 pairs, ascending, oblong or rectangular, margin dentate, sometimes shallowly serrate or subentire, apex rounded or truncate; basal basiscopic lobes in middle pinnules much larger and shallowly pinnatilobate or dentate; veins not prominent on adaxial side, visible abaxially, pinnate, veinlets up to 9 pairs per lobe, usually 2-furcate or pinnate, sometimes simple, oblique. Lamina herbaceous, green or gray-green when dry, not shiny, rachis and costa green-stramineous or light brown, costae and costules abaxially with deciduous short hairs and small scales. Sori linear or shortly linear, up to 7 pairs per lobe, subcostular, reaching to 2/3 of veinlet length; indusia brown when mature, membranous, persistent. Spores subreniform, perispore prominent and hyaline, not rugate, with granular ornamentation.
Evergreen broad-leaved forests, beside streamlets; 300-2200 m. Chongqing, Fujian, Guangdong, Guangxi, Guizhou, Hunan, Sichuan, Taiwan, SE Xizang, Yunnan [Bhutan, India, Kashmir, Nepal].
Diplazium laxifrons is characterized by the naked base of stipe, stalk of lower pinnae black-brown, and basal basiscopic lobes of middle pinnules markedly larger and shallowly pinnatilobate.