Some groups of organisms such as mosses, algae, mushrooms, and lichens are often referred to as plants because they can be found in similar habitats as true plants, but they do not have the same shape or structure as common plants like wildflowers, bushes, or trees.

Also, people assume theses similar species must be plants since they do not look or behave like animals.  However, there are other classifications (categories) of living things in addition to plants and animals, and only one of these (mosses, algae, mushrooms and lichens) is classified as true plants.
 

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Mosses	Algae	Mushrooms	Lichens
Comparison Chart for All Four Similar Groups
The terms "algae", "bacteria", and "fungi" are all plural forms of words even though they do not have an "s" on the end of the word.  The singular word for algae is alga, the singular word for bacteria is bacterium, and the singular word for fungi is fungus.

 
 

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Mosses
Classification:
Mosses are true plants and are in the plant kingdom (Kingdom Plantae).  Plants are able to use sunlight to create sugars that the organism can use for food.  This process is called photosynthesis. They are different from trees, bushes, and other common plants because they are nonvascular (do not contain tubes for transporting water througout the plant). Mosses also do not produce flowers or seeds.	Moss in forest pixabay - ioa8320 Click on image to enlarge it
Identification:
Mosses do not have true leaves, branches, or roots.  They tend to grow in colonies, forming green clumps or mats.  They are usually found in damp, shady areas.  Mosses have leaf-like structures that use sunlight to create sugars for the plant to use (photosynthesis).  They are attached to the surface with root-like strands called rhizoids.	Moss flickr - elycefeliz Click on image to enlarge it
Habitat Requirements:
Mosses can be found throughout the world in habitats that contain moisture because moisture is required for the plant's survival and reproduction.  They tend to grow on the side of trees, rocks, and other shady areas where the soil is dense. They do not tolerate salt water environments.
Moss Life Cycle:
Mosses can reproduce by dividing or by spores (tiny seed-like structures that can only be seen with a microscope). Spores are contained in a structure called a capsule located near the end of a stalk.  The capsule has a covering that falls off when it is time to release the spores. The spores are transferred by water to a new location where the spore can grow into a new plant. Capsules vary in shape and color. New capsules are usually green in color, and many capsules turn red, yellow, or brown as they mature.	Moss Stalks and Capsules Wikimedia Click on image to enlarge it
Ecological Benefits:
Mosses help to break down exposed surfaces and release nutrients back into the ecysostem. Mosses also help control soil erosion by absorbing rainwater.

 

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Algae
Classification:
Algae are in the protist kingdom (Kingdom Protista) This kingdom consists of many of the organisms other than plants, animals, and fungi.  The term algae is used to describe a group of organisms that live in the water that can perform photosynthesis (the process of using sunlight to create sugars that the organism can use as food). Algae do not have true roots, stems, or leaves and are nonvascular (do not contain tubes for transporting water througout the organism).	Algae Diversity Wikimedia - Fleliaer Click on image to enlarge it
Identification:
Many forms of algae are microscopic (not visible to the human eye). Some forms of algae live in colonies and appear as greenish brown, or greenish blue clumps in still or slow moving waters.
	Algae on Rocks Wikimedia - Daniel Mayer Click on image to enlarge it
Habitat Requirements:
Algae are aquatic.  They can grow in freshwater lakes or ponds, and they can grow in saltwater oceans (such as seaweed).  They can tolerate a wide range of temperatures, oxygen levels, and other non-living features in their habitats.  Many algae are found in sunny areas because they need sunlight for the process of photosynthesis (using sunlight to make sugars that the organism can use as food).
	Giant Kelp is the largest marine algae species and the largest seaweed in the world. flickr - NOAA Photo Library (sanc0063) Click on image to enlarge it
Algae Life Cycle:
Algae are able to reproduce through division or fragmentation, a form of reproduction in which an organism breaks into pieces, and each piece is able to grow into a new organism identical to the original. Algae can also reproduce through spores (tiny seed-like structures that can only be seen with a microscope). Algae spores require water for dispersal or movement. Many forms of algae are also able to use a form of reproduction where cells from two individuals fuse together. Ecological Benefits:   Algae are responsible for producing a large percentage of oxygen in Earth's atmosphere. Algae play an important role in the interactions among organisms and what they eat (the food web) because they function as producers. Producers make their own food using energy from sunlight and provide a food source for other organisms.
	Algae PublicDomainPictures.net - Lynn Greyling Click on image to enlarge it

 

 

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Mushrooms (fungi)
Classification:
Kingdom Fungi (yeasts, molds, and mushrooms) Fungi are nonvascular (do not contain tubes for transporting water througout the organism) and are not able to conduct photosynthesis (using sunlight to make sugars that the organism can use as food).	Fairy Ring Mushroom Wikimedia - James St. John Click on image to enlarge it
Identification:
Most mushrooms have a stem with a disc-shaped cap on top.  They range in color including brown, black, white, cream, pink, yellow, red, and purple.
	Red Chanterelli Mushrooms flickr - Thiophene_Guy Click on image to enlarge it
Habitat Requirements:
Mushrooms can grow in a variety of habitats but prefer habitats that are dark and moist such as the forest floor.  They obtain nutrients by breaking down and decomposing other organisms, so they tend to grow in areas where there is debris from plants and animals.

 

Mushroom Life Cycle:
Mushrooms reproduce by spores (tiny seed-like structures that can only be seen with a microscope).  When a spore lands in a favorable location, it grows into a new individual. Eventually the new mushroom will release new spores, and the cycle will continue.  Visit Learn how to make a mushroom spore print and use the Making a Mushroom Spore Print Lesson Plan from Science Learning Hub (PDF) to make your own spore print! Ecological Benefits:	Adobe Stock Click on image to enlarge it
Mushrooms play an important role in the interactions among organisms and what they eat (the food web) because they function as decomposers.  Decomposers break down nonliving organisms and release nutrients back into the ecosystem.
	Turkey Tail Mushroom flickr - Bernard Spragg. NZ Click on image to enlarge it

 

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Lichens
Classification:
A lichen is the result of a mutualistic symbiotic relationship (a relationship in which both organisms live closely together and both organisms benefit from the relationship) between: a fungus (Kingdom Fungi) and an alga (Kingdom Protista) or cyanobacterium (Kingdom Monera). The fungus benefits by gaining energy and nutrients from the alga or cyanobacterium conducting photosynthesis (using sunlight to make sugars that the organism can use as food). In return, the alga or cyanobacterium receives protection from the sun's UV rays through the fungus forming a protective shell. An easy way to remember the relationship:  "When Freddy Fungus met Alice Algae, they took a lichen to each other. Freddy built their house and Alice cooked their meals. Although their relationship is on the rocks, they have decided to stick together."	Lichen on Tree Trunk Wikimedia - Sasata Click on image to enlarge it   Two forms of LIchen PublicDomainPictures.net - Marina Shemesh Click on image to enlarge it

 

The Strangely Popular Lichen Song Music and lyrics © 1991 by Alan AtKisson – from the album “Whole Lotta Shoppin’ Goin’ On,” Rain City Records, 1999

 

Identification:
The portion of the lichen that is visible is called the thallus.  There are several types, each having their own name and identifying traits. Foliose: appear flat and leafy Fruticose: appear wired or tufted Crustose: form a crust over surface Lichen often appear in patches with different sizes and shapes. See photos below.  Each lichen has a structure underneath that allows it to attach to a surface.
Foliose Lichen Wikimedia - Vitaly Charny Click on image to enlarge it	Fruticose Lichen flickr - Martin LaBar Click on image to enlarge it	Crustose Lichen flickr - Miss Anthropology Click on image to enlarge it

 

Habitat Requirements:
Lichens can grow in nearly all terrestrial (land) environments.  The close relationship between the fungi and algae allows both types of organisms to live in a more broad range of environments than they would be able to live as an individual species. Lichens absorb water from the air, so they tend to grow in areas that are foggy or have a moist habitat.  If they dry out, they become brittle, turn a drab gray color, and become dormant.  When there is enough moisture in the air, they appear more bright in color due to the algae or cyanobacteria. Lichens can be found on or inside rocks, on or inside tree bark, and on woody surfaces.  They can also grow on the soil, on mosses, on leaves, or on other lichens.  They can even grow on manmade materials such as concrete, metal, glass, and plastic.
Lichen Life Cycle:
The fungus portion of the lichen produces fruiting parts that release spores (tiny seed-like structures that can only be seen with a microscope).  The fungus that grows from the spore must find a new algae partner, or it will not survive because the algae portion of a lichen does not reproduce. Another form of reproduction is fragmentation of the thallus. A piece of the lichen breaks off and begins gwowing into a new individual.
Ecological Benefits:
Lichens play an important role in the biological weathering of rocks in an ecosystem.  Because they live on the surfaces of rocks and produce chemicals, they begin breaking down the rock, releasing minerals.  This slow breakdown of rocks is the first step in creating soil that will eventually be used by plants. Because lichens absorb water vapor through the air, they require fresh air.  If there are pollutants in the environment, they will absorb those as well.  Lichens can be used as an indicator of pollution for materials like metal, carbon, and sulfur.	Lichen on Rocks pixabay - Hans Click on image to enlarge it
Lichens are used as a food source and nesting materials by a variety of animals. Mammals like deer, squirrels, chipmunks, mice, and bats eat lichen and use beard lichen for nesting materials.  Invertebrates like katydids, grasshoppers, butterflies, spiders, and beetles also feed on lichens.  These animals are also known to live on lichens or use lichens to help camouflage (blend in with the surrounding environment) themselves from other animals.

 

Most beard lichens contain a chemical called usnic acid which has anti-insect and anti-microbial properties.

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Comparison Chart

 

	Mosses	Algae	Mushrooms	Lichens
Classification (Kingdom)	Plant (Kingdom Plantae)	Protist (Kingdom Protista)	Fungus (Kingdom Fungi)	Cyanobacteria or Fungus & Alga (Kingdom Fungi) (Kingdom Protista) (Kingdom Monera)
Identification	Looks like a small clump or flat mat, often green in color, soft to touch, and usually found in damp and shady areas.	In ponds and lakes, looks like greenish-brown or greenish-blue clumps (sometimes stringy) usually found in still or slow moving waters	Often has a short stem with a disc-shaped cap on top;  Ranges in colors including brown, black, white, cream, pink, yellow, red, and purple	Form in patches of different sizes and shapes including (1) Foliose: flat and leafy, (2) Fruticose: wired or tufted, and (3) Crustose: flat crust over surface
Habitat	Moist, shady habitats on the ground or decaying (dying) plant-life	Aquatic (Water) habitats like ponds, lakes & oceans with sunshine	Moist, shady habitats on the ground or decaying (dying) plant-life	Moist, shady habitats usually on rocks and trees
Life Cycle/ Reproduction	Reproduces by fragmentation or spores	Reproduces by fragmentation, spores, or fusing of cells from two separate individuals	Reproduces by spores	Fungus portion of the lichen reproduces by spores; The structure containing the fungus and alga or cyanobacterium can fragment into new individuals
Ecological Benefits	Break down exposed surfaces; Control soil erosion	Produces large amounts of oxygen; Base of the food web in aquatic environments	Decomposers: break down dead organisms and release nutrients back into the system	Biological weathering; Indicator of air pollution

 














































 

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INFORMATION SOURCES
 

Australian National Botanic Gardens and the Australian National Herbarium		Gardening Know How
Current Biology		Live Science - algae Live Science - lichen
Encyclopedia of Life		Biology Online- algae Biology Online - fungi
Lumen Learning		Sciencing.com
USDA Forest Service: Lichen Biology USDA Forest Service: Giant Kelp		Smithsonian: Ocean Find Your Blue