Cyathodium cavernarum

Cyathodium

Thallus yellowish-green to light greenish or flourescent green, thin, delicate, 4-10 x 4-5 mm, often dichotomously branched.

dorsal epidermal cells thin walled, chlorophyl lose; air chambers in single row, partition between air chambers 1-2 cells high with chloroplasts, pores on dorsal surface with 3-4 concentric rings of 4-6 cells; rhizoids smooth walled, scales minute in two rows.