This species is recognized by the narrowly, inconspicuous air chambers in thallus cross section; spores 70-120 µm diameter, and each with incompletely reticulate-areoles on the upper hemisphere, the lower hemisphere with larger areolations and tuberculate on the ridges.
Thalli yellowish-green, forming rosettes; rhizoids mostly smooth, and with some of tuberculae; air-pores simple; thalli cross section 15-25 cells thick, dorsally with 10-20 layers of narrowed chlorophyllose cells, alternating with narrow intercellular cavities, about the half of the thalli, ventrally with 3-5 layers of spongy chlorophyllose cells; epidermal cells rounded, thin-walled, bulging, hyaline; ?Autoicous. Male inflorescences not seen; female inflorescences embedded on the ventral side of thallus at the midrib; sporophytes cleistocarpous; spores with triradiate ridges, 70-120 µm diameter, and each with incompletely reticulate-areoles in the upper hemisphere, the lower hemisphere with larger areolations and tuberculate ridges.
India, Indonesia, and Thailand (Meijer, 1958; Lai et al., 2008, Gradstein, 2011).
On soil in primary, evergreen, hardwood+pine, seasonal forest, granite bedrock, summit of Doi Mon Long, c. 1,438 m elevation; on soil in primary evergreen, seasonal, hardwood forest, granite bedrock, Mahidol Falls, c. 1,058 m elevation; on soil in deciduous-dipterocarp-oak, seasonal hardwood forest, granite bedrock, Daht Mawk Falls, c. 544 m elevation, Doi Come, shale bedrock, c. 413 m elevation.