Lichen Characteristics and Classification

Lichens are symbiotic organisms composed of a fungus and an alga, living together in a mutually beneficial relationship.

Lichens thrive in areas with less pollution and abundant moisture, such as forests. They can also grow in extreme conditions like the Arctic tundra and Antarctic regions.

Lichens are classified based on their growth location. Corticoles grow on bark, saxicoles grow on rocks, and terricoles grow on soil.

The algal member of a lichen is responsible for photosynthesis, producing food for both the fungus and the alga. This is essential for their survival.

The fungal member provides structure and support for the lichen. It also absorbs water and minerals from the environment.

The relationship between the fungus and alga in a lichen is symbiotic, meaning both organisms benefit from their partnership.

While both partners in a lichen benefit, some believe the fungus has more control over the partnership, similar to a master-slave relationship.

Lichens are classified based on the type of fruit body produced by the fungal partner.

A group of lichens characterized by having a fungal partner from the Ascomycotina group, with a disc-shaped fruit body (apothecium).

A group of lichens characterized by having a fungal partner from the Ascomycotina group, with a flask-shaped fruit body (perithecium).

A type of lichen where the thallus is powder-like and loosely attached to the substrate. It appears as a powdery mass.

A type of lichen where the flat thallus is tightly attached to the substrate, resembling a thin crust.

A type of lichen where the thallus is flat, spreading out like a leaf, with lobes. It attaches to the substrate using rhizines.

A type of lichen where the thallus is three-dimensional and upright, often branching like a shrub.

A group of lichens characterized by having a fungal partner from the Basidiomycota group.

A group of lichens characterized by having a fungal partner from the Deuteromycota group.

Hyphae that extend downwards from the lower surface of a lichen thallus, anchoring it to the substrate.

A type of lichen with a branching, shrub-like thallus, such as Usnea.

The outermost layer of a lichen thallus, made of tightly packed fungal hyphae.

The central part of a lichen thallus, containing both algal cells and fungal hyphae.

The central axis of a fruticose lichen, composed of tightly packed fungal hyphae.

Small openings on the upper cortex of some foliose lichens, allowing for gas exchange.

Small cup-like depressions on the lower cortex of some foliose lichens that aid in aeration.

Wart-like outgrowths on the upper surface of a lichen thallus that contain different algal cells from the main thallus.

The reproductive structure of a lichen, typically cup-shaped, containing asci and paraphyses.

Elongated, sterile fungal filaments that grow alongside asci in an apothecium.

A sac-like structure found in lichen apothecia and perithecia, responsible for producing ascospores.

Small, asexual reproductive units produced by basidiomycetes in basidiolichens.

The fertile zone within a lichen apothecium, containing asci and paraphyses. It is the site of ascospore production.

A type of lichen fruiting body that is flask-shaped and contains asci.

A colorless, gelatinous substance found in some lichens, used as a thickener in food and cosmetics.

The brown dye obtained from Parmelia omphalodes is used to dye wool and silk fabrics.

The red and purple dyes can be found in Ochrolechia androgyna and O.tartaria.

This blue dye, also called "Orchil", is made from Cetraria islandica and other lichens. It's used to color woolen goods.

Orcein, the main active compound in the orchil dye, has many uses, like histological studies and dyeing coir.

This dye, extracted from Roccella tinctoria, R.montagnei, and Lasallia pustulata, is used to test the acidity or alkalinity of solutions.

Lichens produce aromatic compounds that find their use in cosmetic products and fragrances.

Lichens, through their holdfast hyphae, can penetrate deep into plant tissue, destroying cell structure and the middle lamella.

Certain lichens like Letharia vulpina are highly poisonous. The toxic compound is vulpinic acid.

Certain lichen species, like Parmelia and Endocarpon miniatum, are consumed in various cuisines around the world, including Indian curry powder and Japanese vegetable dishes.

Lichens like Ramalina traxinea and Cladonia rangifera are used as fodder, providing sustenance for animals in harsh environments, particularly reindeer and muskox in tundra regions.

Lichens have been employed for medicinal purposes since ancient times, with Cetraria islandica and Lobaria pulmonaria being notable examples used to treat lung ailments. Some species also contain compounds with potential antibacterial and anti-inflammatory properties.

Lichens like Lobaria pulmonaria play a crucial role in the process of tanning leather, contributing to the transformation of animal hides into durable materials.

Lichens like Lobaria pulmonaria are used in the brewing process for beer, adding a unique flavor and texture to the final product.

Lichens are a source of natural dyes used in the textile industry. They have been employed since ancient times to color fabrics, contributing to vibrant hues in various textiles.

Certain lichens contain compounds with antibacterial properties, making them valuable ingredients in antiseptic creams and skincare products.

From food sources and animal feed to medicine and industrial applications, lichens offer a remarkable range of uses, highlighting their importance in various fields.