Acanthothecis collateralis

Acanthothecis collateralis is a rare endemic species of script lichen in the family Graphidaceae. Found in the Andaman Islands of India, it was formally described as a new species in 2007 by Urmila Makhija and Bharati Adawadkar. It is distinguished from other Acanthothecis species by its specific arrangement of ascomata and distinct chemical composition. The lichen's thallus has a creamy, off-white colour with a smooth texture that is finely cracked. It is surrounded by a thin, light, and slightly darkened prothallus. The ascomata (spore-producing structures), are lirelline in form and range from 0.2 to 1.2 mm in length. They are usually simple and rarely branched, and found in groups of 2 to 5 lirellae that are arranged parallel to each other, with a whitish rim bordering each group. The disc of the ascomata is narrow and reddish-brown to black in colour with a pruinose surface. The exciple, a protective layer, is brown and non-striate, converging at the base and covered by a thalline......read more on Wikipedia.