lichen

Definition

Any of many symbiotic organisms, being associations of algae and fungi, often found as white or yellow-to-blue–green patches on rocks, old walls, etc.

Etymology

Borrowed from Latin līchēn, from Ancient Greek λειχήν (leikhḗn), from λείχω (leíkhō, “to lick”). Originally used of liverwort; the modern sense first recorded 1715.

Example Sentences

• "The Beaches of Lukannon–the winter wheat so tall, / The dripping, crinkled lichens, and the sea-fog drenching all!"
• "It was the same rich green that one sees on forest moss or on the lichen in caves: plants which like these grow in a perpetual twilight."
• "The nibble marks of the stone adze were still visible, though crusted over with scale lichens in most places."