Plants to 6 cm tall. Rhizomes pale green, sparsely scaly; scales clathrate, lower part ± rounded, margins irregularly branched, apex subulate. Fronds remote, dimorphic; sterile fronds subsessile or with stipe 2-4 mm; lamina orbicular, ovate, or obovate, 1.6-2.5(-5) × 1.2-1.5 cm, base rounded or cuneate, margin entire, apex rounded to subacute; fertile fronds: stipe 3-8 mm; lamina oblong or narrowly lanceolate, 3.5-6(-8) × 2-4 cm, margins revolute when dried. Veins reticulate, with simple included veinlets. Sporangia in linear coenosori, between costa and margin, covered with paraphyses when young.

Lemmaphyllum microphyllum is recorded from NE India (B. Singh et al., J. Threatened Taxa 3: 2288. 2012) but without indication of variety.

According to Knapp (Ferns Fern Allies Taiwan, 464. 2011), the frond size and lamina shape of Lemmaphyllum microphyllum is variable throughout Taiwan.

On trees trunks in forests or rocks in forests; sea level to 1500 m. Anhui, Fujian, Guangdong, Guangxi, Guizhou (Libo), Hainan, Hubei, Jiangxi, Taiwan, Yunnan, Zhejiang [NE India, Japan, S Korea, Vietnam].