Collema tenax is a species of lichen known by the common names jelly lichen, black lichen, and desert lichen.

His palette turns the black lichens that cling to the boulders purple, and the sandy beach blood-red.

The same trick of the light occurs with my low stone walls at Spring Cottage: they only show their fuzzy patches of cream, ochre, red and black lichens in low winter sun.

A massive stone wall barred his way: a construction obviously of great age, overgrown with black and brown lichen.

All around him is a tattered gauze of black lichen.

Cluster enough of them together like some patch of black lichen, and they would eat their way through any ore, extracting the atoms you required for whatever project you had in mind.

Behind it were towering cliffs and wide stretches of boggy tundra broken up by clumps of grey rocks covered in black, curly lichen.

Formed 350 million years ago, with delicate layers of black lichen and orange silica coating its sandstone interior, the Bungle Bungle was known only to the Aborigines until the early part of this century.

Most of the horizontal stones are covered in grey, black and light green lichens and mosses.

The rocks were dotted with round scales of black and green lichen.