Verrucaria nigrescens f. nigrescens
Crustose Lichen
Verrucaria nigrescens f. nigrescens, Lichen. A crustose lichen found on hard limestone. Looks like spots of tar. Upper surface of thallus appears cracked into smaller islands. Reproductive bodies are microscopic pits in small mounds on the upper thallus called perithecia. Lower surface penetrates the rock.
Photograph detail
Slide 1: Verrucaria nigrescens f. nigrescens, a crustose lichen. Thallus on limestone. Collected from Redmire Quarry. April.
Slide 2: Verrucaria nigrescens f. nigrescens, a crustose lichen. Thallus on limestone, showing cracked structure. Collected from Redmire Quarry. April.
Slide 3: Verrucaria nigrescens f. nigrescens, a crustose lichen. Thallus on limestone, showing mounds cotaining perithecia. Collected from Redmire Quarry. April.
Slide 4: Verrucaria nigrescens f. nigrescens, a crustose lichen. Squash of thallus showing black fungal component, green algal cells and calcite crystals from the rock. Photographed at x400, brightfield illumination. Collected from Redmire Quarry. April.
Slide 5: Verrucaria nigrescens f. nigrescens, a crustose lichen. Thallus on limestone. Redmire Quarry. April.
Slide 6: Verrucaria nigrescens f. nigrescens, a crustose lichen. Habitat. Redmire Quarry. April.
Slide 7: Verrucaria nigrescens f. nigrescens, a crustose lichen. Large black patches on quarry face. Redmire Quarry. July.