1) Fern genus 2) Genus hymenophyllum 
Hymenophyllum is a genus of ferns in the family Hymenophyllaceae. Its name means `membranous leaf`, referring to the very thin translucent tissue of the fronds, which gives rise to the common name filmy fern for this and other thin-leaved ferns. The leaves are generally only one cell thick and lack stomata, making them vulnerable to desiccation......
(from the article `fern`) ...forest epiphytes; mostly tiny ferns with blades only 1 or 2 cells in thickness between veins; spores globose, green; gametophyte ribbon-shaped or ...
[n] - type genus of the Hymenophyllaceae: filmy ferns