English: A lichen - Dermatocarpon luridum. This rather inconspicuous lichen was growing on a rock in the upper part of a beach (right next to the location of another species: 1054150).

Dermatocarpon luridum is the charred-looking species that runs across the middle of the image from left to right. When dry, as is the case here, it is light brown; it appears greenish when wet. One interesting feature is the pattern of dots on its surface (best seen just above and to the right of the centre of the image). Through a hand-lens, these dots can be seen to be arranged in a regular pattern; they are the openings of spore-producing chambers called perithecia.

The very distinctive pattern of dots on the surface is well illustrated in a line drawing at: http://www.fs.fed.us/r6/aq/lichen/drawings.htm#D (click on the species name Dermatocarpon luridum in the list to see the drawing).