lichen

[ lahy-kuhn ]

noun

1. any complex organism of the group Lichenes, composed of a fungus in symbiotic union with an alga and having a greenish, gray, yellow, brown, or blackish thallus that grows in leaflike, crustlike, or branching forms on rocks, trees, etc.
2. Pathology. any of various eruptive skin diseases.

verb (used with object)

1. to cover with or as if with lichens.

lichen

/ ˈlɪtʃən; ˈlaɪkən /

noun

1. an organism that is formed by the symbiotic association of a fungus and an alga or cyanobacterium and occurs as crusty patches or bushy growths on tree trunks, bare ground, etc. Lichens are now classified as a phylum of fungi ( Mycophycophyta )
2. pathol any of various eruptive disorders of the skin

lichen

/ lī′kən /

1. The mutualistic symbiotic association of a fungus with an alga or a cyanobacterium, or both. The fungal component of a lichen absorbs water and nutrients from the surroundings and provides a suitable environment for the alga or cyanobacterium. These live protected among the dense fungal hyphae and produce carbohydrates for the fungus by photosynthesis. Owing to this partnership, lichens can thrive in harsh environments such as mountaintops and polar regions. The more familiar lichens grow slowly as crusty patches, but lichens are found in a variety of forms, such as the tall, plantlike reindeer moss. The association between the different organisms in a lichen is so close that lichens are routinely referred to as a single organism, and scientists classify lichens using the name of the fungal component.

Derived Forms

• ˈlichenˌoid, adjective
• ˈlichened, adjective
• ˈlichen-ˌlike, adjective
• ˈlichenous, adjective

Other Words From

• lichen·i·zation noun
• lichen·like adjective
• un·lichened adjective

Word History and Origins

Origin of lichen¹

1595–1605; < Latin līchēn < Greek leichḗn

Word History and Origins

Origin of lichen¹

C17: via Latin from Greek leikhēn, from leikhein to lick

Example Sentences

They are constructed by communities of fungi, lichens, cyanobacteria and other microorganisms that live in the topmost millimeters of soil and produce adhesive substances that clump soil particles together.

From Science News

Today, mosquitoes, trees, mosses, lichens and snow dominate this Siberian landscape.

From Science News For Students

Old Man’s Beard lichens fluttered in the breeze as I crept up and around the most densely-packed timberland I had ever seen.

From Outside Online

After a strenuous two-day hike through crimson dwarf birch, spongy lichens, and anxiety-inducing tussocks, we pitched our tents at the base of the most spectacular mountains I have ever seen.

From Outside Online

I paddled into the waves, heading straight towards a cluster of small islands, their rocky outcroppings freckled with pale lichens and mosses.

From Outside Online

“We resemble a successful lichen, a ravaging bloom of algae, a mold enveloping a fruit,” reads the text.

From The Daily Beast

That grey old house, with high lichen-stained roof and narrow windows—where but in sunny France could one see its like?

From Project Gutenberg

To these they often add tufts of wool, and lichen, and the whole is fastened together by a kind of clay.

From Project Gutenberg

As far as I could see there were no grass, no weeds, no flowers; the earth was covered with a kind of lichen, uniformly blue.

From Project Gutenberg

The thin tendrils of a lichen, here and there twining on a damp mass of stone, are the only traces of life.

From Project Gutenberg

A boy pushed the bracken and ferny grey and green wattle sprays from before a lichen-grown wooden cross.

From Project Gutenberg