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Help me identify this… plant? fungus?

Help me identify this… plant? fungus?


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Today I found several of these in my back garden in Sydney NSW, Australia (specifically the north shore). They seem like flowers, except I don't see any attached plant and they have a weird brown goo around the mouth. I've never seen anything like this. Any ideas?


After some Googling, it seems maybe this is a stinkhorn fungus, specifically Aseroe rubra.


Help me identify this… plant? fungus? - Biology

Fungi, latin for mushroom, are eukaryotes which are responsible for decomposition and nutrient cycling through the environment.

Learning Objectives

Describe the role of fungi in the ecosystem

Key Takeaways

Key Points

  • Fungi are more closely related to animals than plants.
  • Fungi are heterotrophic: they use complex organic compounds as sources of energy and carbon, not photosynthesis.
  • Fungi multiply either asexually, sexually, or both.
  • The majority of fungi produce spores, which are defined as haploid cells that can undergo mitosis to form multicellular, haploid individuals.
  • Fungi interact with other organisms by either forming beneficial or mutualistic associations (mycorrhizae and lichens ) or by causing serious infections.

Key Terms

  • mycorrhiza: a symbiotic association between a fungus and the roots of a vascular plant
  • spore: a reproductive particle, usually a single cell, released by a fungus, alga, or plant that may germinate into another
  • lichen: any of many symbiotic organisms, being associations of fungi and algae often found as white or yellow patches on old walls, etc.
  • Ascomycota: a taxonomic division within the kingdom Fungi those fungi that produce spores in a microscopic sporangium called an ascus
  • heterotrophic: organisms that use complex organic compounds as sources of energy and carbon

Introduction to Fungi

The word fungus comes from the Latin word for mushrooms. Indeed, the familiar mushroom is a reproductive structure used by many types of fungi. However, there are also many fungi species that don’t produce mushrooms at all. Being eukaryotes, a typical fungal cell contains a true nucleus and many membrane-bound organelles. The kingdom Fungi includes an enormous variety of living organisms collectively referred to as Ascomycota, or true Fungi. While scientists have identified about 100,000 species of fungi, this is only a fraction of the 1.5 million species of fungus probably present on earth. Edible mushrooms, yeasts, black mold, and the producer of the antibiotic penicillin, Penicillium notatum, are all members of the kingdom Fungi, which belongs to the domain Eukarya.

Examples of fungi: Many species of fungus produce the familiar mushroom (a) which is a reproductive structure. This (b) coral fungus displays brightly-colored fruiting bodies. This electron micrograph shows (c) the spore-bearing structures of Aspergillus, a type of toxic fungi found mostly in soil and plants.

Fungi, once considered plant-like organisms, are more closely related to animals than plants. Fungi are not capable of photosynthesis: they are heterotrophic because they use complex organic compounds as sources of energy and carbon. Some fungal organisms multiply only asexually, whereas others undergo both asexual reproduction and sexual reproduction with alternation of generations. Most fungi produce a large number of spores, which are haploid cells that can undergo mitosis to form multicellular, haploid individuals. Like bacteria, fungi play an essential role in ecosystems because they are decomposers and participate in the cycling of nutrients by breaking down organic and inorganic materials to simple molecules.

Fungi often interact with other organisms, forming beneficial or mutualistic associations. For example most terrestrial plants form symbiotic relationships with fungi. The roots of the plant connect with the underground parts of the fungus forming mycorrhizae. Through mycorrhizae, the fungus and plant exchange nutrients and water, greatly aiding the survival of both species Alternatively, lichens are an association between a fungus and its photosynthetic partner (usually an alga). Fungi also cause serious infections in plants and animals. For example, Dutch elm disease, which is caused by the fungus Ophiostoma ulmi, is a particularly devastating type of fungal infestation that destroys many native species of elm (Ulmus sp.) by infecting the tree’s vascular system. The elm bark beetle acts as a vector, transmitting the disease from tree to tree. Accidentally introduced in the 1900s, the fungus decimated elm trees across the continent. Many European and Asiatic elms are less susceptible to Dutch elm disease than American elms.

In humans, fungal infections are generally considered challenging to treat. Unlike bacteria, fungi do not respond to traditional antibiotic therapy because they are eukaryotes. Fungal infections may prove deadly for individuals with compromised immune systems.

Fungi have many commercial applications. The food industry uses yeasts in baking, brewing, and cheese and wine making. Many industrial compounds are byproducts of fungal fermentation. Fungi are the source of many commercial enzymes and antibiotics.


Help us to make the First Nature fungi pages even better

If you have taken pictures of beautiful, unusual or just plain weird fungi and would be willing to have them shown on the First Nature website (with proper acknowledgement to you, of course) to help other people learn more about and enjoy the fascination of fungi, please see our Contributors guide.

If you have found this information helpful, please consider helping to keep First Nature online by making a small donation towards the web hosting and internet costs.

Any donations over and above the essential running costs will help support the conservation work of Plantlife, the Rvers Trust and charitable botanic gardens - as do author royalties and publisher proceeds from Pat and Sue's nature books - available from First Nature.


How it works?

To identify a plant you simply need to simply snap a photo of the plant, and the app will tell you what it is in a matter of seconds!
PlantSnap can currently recognize 90% of all known species of plants and trees, which covers most of the species you will encounter in every country on Earth.


Not all fungi feed on dead organisms. Many are involved in symbiotic relationships, including parasitism and mutualism.

Fungi as Parasites

In a parasitic relationship, the parasite benefits while the host is harmed. Parasitic fungi live in or on other organisms and get their nutrients from them. Fungi have special structures for penetrating a host. They also produce enzymes that break down the host&rsquos tissues.

Parasitic fungi often cause illness and may eventually kill their host. They are the major cause of disease in agricultural plants. Fungi also parasitize animals, such as the insect pictured in Figure below. Fungi even parasitize humans. Did you ever have athelete&rsquos foot? If so, you were the host of a parasitic fungus.

Parasitic Fungus and Insect Host. The white parasitic fungus named Cordyceps is shown here growing on its host&mdasha dark brown moth.

Mutualism in Fungi

Fungi have several mutualistic relationships with other organisms. In mutualism, both organisms benefit from the relationship. Two common mutualistic relationships involving fungi are mycorrhiza and lichen.

  • A mycorrhiza is a mutualistic relationship between a fungus and a plant. The fungus grows in or on the plant roots. The fungus benefits from the easy access to food made by the plant. The plant benefits because the fungus puts out mycelia that help absorb water and nutrients. Scientists think that a symbiotic relationship such as this may have allowed plants to first colonize the land.
  • A lichen is an organism that results from a mutualistic relationship between a fungus and a photosynthetic organism. The other organism is usually a cyanobacterium or green alga. The fungus grows around the bacterial or algal cells. The fungus benefits from the constant supply of food produced by the photosynthesizer. The photosynthesizer benefits from the water and nutrients absorbed by the fungus. Figurebelow shows lichen growing on a rock.

Lichen Growing on Rock. Unlike plants, lichen can grow on bare rocks because they don&rsquot have roots. That&rsquos why lichens are often pioneer species in primary ecological succession. How do lichen get water and nutrients without roots?

Some fungi have mutualistic relationships with insects. For example:

  • Leafcutter ants grow fungi on beds of leaves in their nests. The fungi get a protected place to live. The ants feed the fungi to their larvae.
  • Ambrosia beetles bore holes in tree bark and &ldquoplant&rdquo fungal spores in the holes. The holes in the bark give the fungi an ideal place to grow. The beetles harvest fungi from their &ldquogarden.&rdquo

Related Biology Terms

  • Heterotroph – An organism that cannot make its own food and must obtain nutrients from other organic sources.
  • Hyphae – Branching filaments of a fungus.
  • Mycelium – A network of hyphae.
  • Yeast – Single-celled fungi.

1. Which of these is NOT a fungus?
A. Mold
B. Mushroom
C. Algae
D. Yeast

2. What is a mycorrhiza?
A. A network of hyphae
B. A fungus that has hyphae without septa
C. A symbiotic association of plant roots and fungi
D. A symbiotic association of bacteria and fungi

3. Which fungi have greatly reduced populations of harlequin frogs?
A. Chytrids
B. Ascomycetes
C. Basidiomycetes
D. Zygomycetes


Plant ID websites

An essential website is the USDA Natural Resources Conservation Service Plants Database. This huge database includes a search function utilizing a common name or scientific name, photos and illustrations, geographic distribution maps, and links to other resources with even more information about a specific plant.

Although designated as a “weed identification guide” specifically for the southeastern U.S., this website by Virginia Tech includes detailed information with excellent supporting photos. The guide carefully notes similar looking plants and provides a link to the similar plant’s description. The “weeds” found in the southeastern U.S. can also be found in other parts of the U.S. and the world ( e.g. , dandelion, white clover, St. Johnswort, plantain).

The Lady Bird Johnson Wildflower Center, located at the University of Texas at Austin, has a wonderful Native Plant Database. By selecting some typical plant characteristics, you can obtain helpful search results — which reduces the number of plants to consider as you identify an unknown plant.

Southeasternflora.com utilizes a simple online key to identify plants in the southeastern portion of the U.S. Key characteristics include flower color, plant form, leaf type and leaf arrangement. You can also search on a plant’s common or scientific (species or family) name. Each featured plant includes numerous excellent photos along with basic information.

Missouriplants.com is an excellent resource when searching by the scientific name of a plant. The site includes detailed photographs with notes on stems, leaves, flowers, inflorescence, habitat, etc. — with an emphasis on plants found in Missouri (although the plant photos were taken throughout the U.S.).

The USDA Natural Resources Conservation Service “National Plant Data Center” includes interactive keys (polyclave key) and plant character data sets for some groups of plants. The data is available for grasses (Poaceae family) and legumes (Fabaceae family) — among other plant families — for each state in the U.S.

For an extensive list of Internet resources, visit the Vocational Information Center – Horticulture Basics and Plant Identification. I continue to review this list and will gradually highlight some of my favorites here. The description on this web page notes that the learning resources link to: “classification of plants, plant glossaries, plant cell basics, plant propagation, photosynthesis, biomes, habitats, hardiness zones, plant identification, plant images, endangered plants, and history of horticulture.” The links and information are global.

Dave’s Garden claims to be “the largest plant database in the world” and focuses on plants favored by gardeners. It’s a great resource for photos to confirm a plant’s identification.

Southwest Colorado Wildflowers focusses on wildflowers, ferns and trees in the Four Corners area (Colorado, New Mexico, Arizona and Utah). At this well-designed website, you can learn basic plant identification skills, pick up great tips for taking photographs of plants, and identify plants.

The Virtual Herbarium utilizes an interactive key to identify the family for a plant. Two sets of data are included on the site: (1) 248 species of trees in Miami, Florida and (2) flowering plants of Jamaica. In addition, there are links to other interactive keys available on the internet.


A guide to what's here

This is a long section and you may not be interested in all the topics. To help you decide if there's something of interest to you, here are brief descriptions of the sub-sections. If nothing else - try Macroscopic features. If you haven't looked closely at fungi, the photos alone will show you a variety of features you can see with the naked eye or with a magnifying glass.

  • Classification vs. identification
    An explanation of the difference between classification and identification.
  • The classification hierarchy
    A brief outline of the classification hierarchy, with a link to more detail.
  • Classification and identification again
    Why aren't just the "obvious" features used in fungal classification and identification?
  • Macroscopic features
    Links to explanations and illustrations of many of the naked-eye features used in the study of fungi. If nothing else, it may make you look at common fungi from a new perspective.
  • Microscopic structures
    An introduction to some of the basic microscopic features used in the study of fungi.
  • Non-structural features
    You need more than macroscopic and microscopic structural features for a deeper understanding of fungi. Here are some other methods that can shed light on the fungal world.
  • Relationships that are and are not
    Relationships aren't always obvious. Here are some examples.
  • Classification and identification - final words
    A brief case study that brings us back to where we started.

Classification vs. identification

Before going further it is worth pointing out the difference between classification and identification.

Classification answers questions of the sort: How is this fungus related to other fungi?

Identification addresses the more immediate question: What's the name of the specimen in front of me?

To say that two organisms are related is the same as saying they have a common ancestor - perhaps in the fairly recent past or possibly in the distant past. Depending on whether that common ancestor lived in the recent or distant past we can talk of the two organisms as being closely or distantly related. This reflects the everyday idea of human relationships, for we say that two people are closely related if they have the same parents but talk of them as distant relatives if great-grandparents are their most recent common ancestors.

Classification therefore deals with evolutionary history and a good classification scheme should group evolutionarily close organisms near one another. This demands a good understanding of many different aspects of fungal structure (both macroscopic and microscopic) and fungal biology, since the different aspects provide different types of evidence regarding relationships. In order to develop a sound classification, all the evidence must be assessed.

In essence, classification involves the creation of pigeonholes into which related fungi will be placed. Once the different pigeonholes have been created, each is given a unique name to enable easy communication between mycologists.

Continuing with the pigeonhole analogy, identification is akin to picking up the specimen in front of you and putting it in the right pigeonhole. There are numerous fungal identification guides and, while they differ in scope and content, the actual identification procedure is much the same in each of them. You are asked a series of questions about the features of your specimen, with each successive question narrowing down the possible pigeonholes a bit more until you are left with just one. It's often a fairly mechanical process and mostly doesn't need any understanding of fungal classification. That is, you often don't need to understand how those pigeonholes were created. It's a bit like cooking - if you follow the instructions in the recipe you'll bake yourself a delicious cake. You must be able to recognize things such as eggs, flour, milk and yeast but you don't need to know the function of any of these ingredients. Of course, a good cook knows what the ingredients do and can then intelligently substitute ingredients or vary the recipe for particular purposes. Similarly, knowledge of fungal classification will give you a better grasp of the fungal world, allow you to take intelligent shortcuts in identification and help guard against misunderstandings.

The classification hierarchy

There are different degrees of relatedness in the living world and these varying degrees of relatedness lead to the concept of a hierarchy of different levels of classification - kingdom, division (or phylum), class, order, family, genus, species. That sequence goes from broad to fine. That is, a kingdom contains a number of divisions, each division contains a number of classes, each class contains a number of orders and so on.

If you are unfamiliar with the technical usages of any of the above terms, there's a simplified introduction to the essential concepts here CLASSIFICATION HIERARCHY, SPECIES NAMES AND IDENTIFICATION SECTION.

A species name is a unique combination of two Latin (or pseudo-Latin) words. That combination is called a binomial. When photos on this website are labelled with species names, those names (such as Schizophyllum commune in this instance) <<042>> are examples of binomials. Going back to the earlier pigeonhole analogy, we could say one of our pigeonholes has the label Schizophyllum commune on it.

Once again, if you are unfamiliar with the structure of scientific names, the basic facts are explained here CLASSIFICATION HIERARCHY, SPECIES NAMES AND IDENTIFICATION SECTION >>. That link also contains some examples of the hierarchy, by giving the various levels for a couple of fungal species and also contains some information on related topics.

All the (macro) fungi that are the subject of this website belong to one kingdom (called the Eumycota) and there's more to the Eumycota than that, but the rest of the Eumycota are beyond the scope of this website.

As noted in the <> those (macro) fungi can be divided into two groups, depending on whether spores are produced in asci or on basidia. Within the classification hierarchy, fungi that have asci constitute a Division called the Ascomycota and those with basidia constitute a Division called the Basidiomycota. These two technical names are obviously very similar to the ordinary English words ascomycete and basidiomycete. People often talk of "high level" or "low level" classificatory features. The former are used in the definition of higher groupings such as division and class while the latter are used at lower levels - for example, to define genera and species. In these terms asci and basidia are very high level classificatory features.

There are microfungal basidiomycetes and ascomycetes, but they are beyond the scope of this website.

While the (macro) fungi are contained within two divisions of kingdom Eumycota, the full range of organisms (macro and micro) that are likely to be called "fungi" are found in three kingdoms. An explanation of the features used in the high level classification of all those "fungi" is given in <>.

There'll now be a brief detour on the subject of classification and identification. After that there'll be examples of the sorts of features that are used in classification or identification.

Classification and identification again


Omphalotus nidiformis (above) glowing in the dark

Omphalotus nidiformis (left)

Many of the features or techniques used in classification are also used routinely in specimen identification and often that is inevitable. For example, luminosity is one of the defining characteristics of the genus Omphalotus, an example of which is shown in the accompanying photos. <<001, 002>> This easily observable classificatory feature is obviously a very useful identification feature as well.

However, classificatory features are not always necessary in day-to-day identification work. For example, DNA analysis is now in widespread use for the investigation of relationships between different organisms. DNA analysis is often in the news because of its use as a forensic tool in criminal investigations. There will be a little bit more about DNA analysis later. For the moment it is enough to know that DNA analysis is a powerful classification tool but it does require specialist equipment and is impractical in much routine identification work. So mycologists often use the more easily observed features for much of the day-to-day identification work.

If a specialised technique is essential for classifying fungi, how can you ever avoid using it for identification? The important thing is that, while our ideas of how we classify fungi will change (which will sometimes involve a change of name), the fungi themselves won't change. Some fungi are so distinctive, and with no look-alikes, that you can always recognize them by those distinctive features. Of course, the species name you give may change with time – but the identification features you look for remain unchanged. It's a bit like a friend who marries several times. You might need the marriage certificates to prove the changing relationships – but those bits of paper are irrelevant for identification. You’ll always recognize your friend by his distinctive appearance.

The species Calostoma fuscum <<070>> is immediately identifiable on the basis of naked eye features. However, its relationships to other fungi had been debated for a long time, until some fairly recent DNA studies. There’s more about this below in RELATIONSHIPS THAT ARE AND ARE NOT

People sometimes ask: If you can identify something using easily observed features, why not use those features for classification as well and forget about "impractical" techniques such as DNA analysis? Simply because reliance on the easily observed features can lead to incorrect conclusions about relationships. To take a trivial human example, suppose we have two brothers. One spends all summer indoors (and remains fair-skinned) while the other is on a sunny Australian beach each day (and develops a deep tan). Using just the easily observed feature of skin colour, an alien visiting earth at the end of summer could mistakenly conclude that the brothers are unrelated. On the other hand, a more detailed examination would have shown the alien that both brothers could produce dark skin pigments and that skin colour was a misleading classificatory feature. The darker skin on one brother was simply his body's response to a sunny environment.

Similarity in DNA reflects evolutionary closeness, hence the usefulness of DNA analysis. Of course, an organism's outward form is heavily dependent on its DNA but, as the tanned skin example shows, some aspects of outward form may be no more than responses to the surrounding environment, rather than being inherent features of the organism. A classification scheme should not use features that can be easily modified by the surroundings. Experience has shown that some outward features, once heavily relied on for classifying fungi, are as misleading as tanned skin in the above example.

By the way, don't think that colour is unimportant in fungal classification (or identification). Often it is a crucial feature - but not always. As in the example of the two brothers, it is important to know the reason behind the colours. Each of the following photos shows the species Flammulina velutipes. In the wild this mushroom has the slightly sticky, orange cap. The white form appears when it is grown in the dark, in an atmosphere with a high carbon dioxide level and with the developing clusters of mushrooms forced to grow out through long tubes. You can see that cultivated form in many supermarkets or Asian grocery stores, where it is sold under the name enokitake.

GET FLAMMULINA VELUTIPES PHOTOS

  • Macroscopic features
    Links to explanations and illustrations of many of the naked-eye features used in the study of fungi. If nothing else, it may make you look at common fungi from a new perspective.
  • Microscopic structures
    An introduction to some of the basic microscopic features used in the study of fungi.
  • Non-structural features
    You need more than macroscopic and microscopic structural features for a deeper understanding of fungi. Here are some other methods that can shed light on the fungal world.
  • Relationships that are and are not
    Relationships aren't always obvious. Here are some examples.

Classification and identification - final words

This section has given you a quick tour of some tools of fungal classification and pointed out a few non-intuitive relationships between various fungi. Over the past three centuries fungal classification has changed, with microscopic features now of great importance and there's a brief account of the timing of some of the basic microscopic discoveries in the <>. Various other aspects of fungal behaviour provide additional information. Each investigatory tool, whether it be fruiting body shape, spore features, mating tests or DNA analysis provides a different way of looking at fungi. In order to come up with a robust classification scheme, it is necessary to approach fungi with these different tools and assess the information that each provides.

Sometimes the evidence from one approach may contradict the evidence from another approach. For example, the old classification (relying on "inkiness" as an important feature) put all the Inkcaps into the genus Coprinus - but DNA analysis says the Inkcaps don't all belong in the one genus - in fact, not even in the one family. What do you do when you get conflicting evidence? Obviously, re-check the methods to see if there have been any mistakes. If not, you can either accept one lot of evidence as more reliable than the other or leave the issue unresolved. Not necessarily a very happy result, but sometimes it's necessary to put a problem aside and wait for future developments to resolve the issue.

In the case of Coprinus, people redid the DNA analysis, using improved techniques, and still came up with the same conclusion. One thing to note is that the DNA evidence didn't come as a great surprise to some mycologists, since there had been considerable debate (over a hundred years) about the correct relationships between the Coprinus species. The DNA results prompted re-examination of the macroscopic and microscopic structures in various Coprinus species.

The DNA evidence indicates that Coprinus comatus and a few other species form a closely related group, so there's a good argument for grouping those species into a genus of their own. Apart from the DNA evidence, the species in this group share some microscopic and macroscopic features that aren't found in other Coprinus species. One macroscopic feature is very easy to see. The stem of Coprinus comatus is pipelike, rather than solid, but the pipe isn't empty. There's a wispy cord, composed of a bundle of hyphae, that runs the length of the hollow centre and has no known purpose. This photo shows a dried specimen of Coprinus comatus, with the stem cut open to reveal the wispy central cord. The cord is present in the other species that the DNA evidence groups with Coprinus comatus - but the cord is absent from those Coprinus species that are not grouped with Coprinus comatus.

It's interesting to note that in a painting of Coprinus comatus, published in 1781 in a book by the French naturalist Jean Baptiste Francois 'Pierre' Bulliard (1752-1793), this cord showed very clearly. However inkiness was thought to be an important feature and so it was used in the original definition of Coprinus. If (and the 'if' must be stressed) the species in the Coprinus comatus group are separated from the rest of the Coprinus species and put into a genus of their own, that hyphal cord will be a very useful and easy-to-use identification feature for the new genus. Inkiness would still remain a very useful feature, but one that needs to be augmented. While inkiness would no longer take you to just one genus, it would take you to a small group of genera, after which you'd use additional evidence (such as the hyphal cord) to determine the genus.

At present, the status of the species in Coprinus is being debated and more work is needed before the debate is settled and any new genera agreed to.

However the Coprinus work does show that whenever a specialised technique is used to help classify fungi, it is essential to re-examine other features to see if there is anything that is correlated with the results from the specialised technique. That may not always happen but, in the current example, the cord in the hollow stem is an easily observed feature that is correlated with the genetic evidence. Therefore the cord would be ideal for identification purposes, assuming the Coprinus comatus group is placed in its own genus.

This brings us back to where we started. Remember that classification and identification are two different things. While classification must bring together many different strands of evidence (using a variety of methods), for identification we use whatever features make it easiest to answer the question: "What's the name of the specimen in front of me?".


Plant Benefits from Mycorrhizae

Mycorrhiza associations are particularly beneficial in areas where the soil does not contain sufficient nitrogen and phosphorus, as well as in areas where water is not easily accessible. Because the mycorrhizal mycelia are much finer and smaller in diameter than roots and root hairs, they vastly increase the surface area for absorption of water, phosphorus, amino acids, and nitrogen—almost like a second set of roots! As these nutrients are essential for plant growth, plants with mycorrhizal associations have a leg-up on their non-mycorrhizal associated counterparts that rely solely on roots for the uptake of materials. Without mycorrhiza, plants can be out-competed, possibly leading to a change in the plant composition of the area.

Additionally, studies have found that plants with mycorrhizal associations are more resistant to certain soil-borne diseases. In fact, mycorrhizal fungi can be an effective method of disease control. In the case of sheathing mycorrhiza, they create a physical barrier between pathogens and plant roots. Mycorrhiza also thicken the root’s cell walls through lignifications and the production of other carbohydrates compete with pathogens for the uptake of essential nutrients stimulate plant production of metabolites that increases resistance to disease stimulate flavonolic wall infusions that prevent lesion formation and invasion by pathogens and increase plant root concentrations of orthodihydorxy phenol and other allochemicals to deter pathogenic activity. In addition to disease resistance, mycorrhizal fungi can also impart to its host plant resistance to toxicity and resistance to insects, ultimately improving plant fitness and vigor.

In more complex relationships, mycorrhizal fungi can connect individual plants within a mycorrhizal network. This network functions to transport materials such as water, carbon, and other nutrients from plant to plant, and even provides some type of defense communication via chemicals signifying an attack on an individual within the network. Not only can plants use these signals to start producing natural insect repellants, they can also use them to start producing an attractant to bring in natural predators of the plant’s pests!

In some cases, mycorrhizal fungi allow plants to bypass the need for soil uptake, such as trees in dystrophic forests. Here, phosphates and other nutrients are taken directly from the leaf litter via mycorrhizal hyphae.

Mycorrhizal fungi are also able to interact with and change the environment in the favor of the host plants—namely, by improving soil structure and quality. The filaments of mycorrhizal fungi create humic compounds, polysaccharides, and glycoproteins that bind soils, increase soil porosity, and promote aeration and water movement into the soil. In environments that have highly compacted or sandy soils, improved soil structure can be more important for plant survival than nutrient uptake.

Some ectomycorrhizal associations create structures that host nitrogen-fixing bacteria, which would largely contribute to the amount of nitrogen taken up by plants in nutrient-poor environments, and would play a large part in the nitrogen cycle. The mycorrhizal fungi, however, do not fix nitrogen themselves.


THE LIVING SOIL: FUNGI

Fungi are microscopic cells that usually grow as long threads or strands called hyphae, which push their way between soil particles, roots, and rocks. Hyphae are usually only several thousandths of an inch (a few micrometers) in diameter. A single hyphae can span in length from a few cells to many yards. A few fungi, such as yeast, are single cells.

Hyphae sometimes group into masses called mycelium or thick, cord-like &ldquorhizomorphs&rdquo that look like roots. Fungal fruiting structures (mushrooms) are made of hyphal strands, spores, and some special structures like gills on which spores form. A single individual fungus can include many fruiting bodies scattered across an area as large as a baseball diamond.

Fungi perform important services related to water dynamics, nutrient cycling, and disease suppression. Along with bacteria, fungi are important as decomposers in the soil food web. They convert hard-to-digest organic material into forms that other organisms can use. Fungal hyphae physically bind soil particles together, creating stable aggregates that help increase water infiltration and soil water holding capacity.

Soil fungi can be grouped into three general functional groups based on how they get their energy.

  • Decomposers &ndash saprophytic fungi &ndash convert dead organic material into fungal biomass, carbon dioxide (CO2), and small molecules, such as organic acids. These fungi generally use complex substrates, such as the cellulose and lignin, in wood, and are essential in decomposing the carbon ring structures in some pollutants. A few fungi are called &ldquosugar fungi&rdquo because they use the same simple substrates as do many bacteria. Like bacteria, fungi are important for immobilizing, or retaining, nutrients in the soil. In addition, many of the secondary metabolites of fungi are organic acids, so they help increase the accumulation of humic-acid rich organic matter that is resistant to degradation and may stay in the soil for hundreds of years.
  • Mutualists &ndash the mycorrhizal fungi &ndash colonize plant roots. In exchange for carbon from the plant, mycorrhizal fungi help solubolize phosphorus and bring soil nutrients (phosphorus, nitrogen, micronutrients, and perhaps water) to the plant. One major group of mycorrhizae, the ectomycorrhizae (see third photo below), grow on the surface layers of the roots and are commonly associated with trees. The second major group of mycorrhizae are the endomycorrhizae that grow within the root cells and are commonly associated with grasses, row crops, vegetables, and shrubs. Arbuscular mycorrhizal (AM) fungi are a type of endomycorrhizal fungi. Ericoid mycorrhizal fungi can by either ecto- or endomycorrhizal.
  • The third group of fungi, pathogens or parasites, cause reduced production or death when they colonize roots and other organisms. Root-pathogenic fungi, such as Verticillium, Pythium, and Rhizoctonia, cause major economic losses in agriculture each year. Many fungi help control diseases. For example, nematode-trapping fungi that parasitize disease-causing nematodes, and fungi that feed on insects may be useful as biocontrol agents.

Many plants depend on fungi to help extract nutrients from the soil. Tree roots (brown) are connected to the symbiotic mycorrhizal structure (bright white) and fungal hyphae (thin white strands) radiating into the soil.

Credit: Randy Molina, Oregon State University, Corvallis. P lease contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

Fungus beginning to decompose leaf veins in grass clippings.

Credit: No. 48 from Soil Microbiology and Biochemistry Slide Set. 1976. J.P. Martin, et al., eds. SSSA, Madison WI. P lease contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

Ectomycorrhizae are important for nutrient absorption by tree and grape roots. The fungus does not actually invade root cells but forms a sheath that penetrates between plant cells. The sheath in this photo is white, but they may be black, orange, pink, or yellow.

Credit: USDA, Forest Service, PNW Research Station, Corvallis, Oregon. P lease contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

The dark, round masses inside the cells of this clover root are vesicules for the arbuscular mycorrhizal fungus (AM).

Credit: Elaine R. Ingham. P lease contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

Where Are Fungi?

Saprophytic fungi are commonly active around woody plant residue. Fungal hyphae have advantages over bacteria in some soil environments. Under dry conditions, fungi can bridge gaps between pockets of moisture and continue to survive and grow, even when soil moisture is too low for most bacteria to be active. Fungi are able to use nitrogen up from the soil, allowing them to decompose surface residue which is often low in nitrogen.

Fungi are aerobic organisms. Soil which becomes anaerobic for significant periods generally loses its fungal component. Anaerobic conditions often occur in waterlogged soil and in compacted soils.

Fungi are especially extensive in forested lands. Forests have been observed to increase in productivity as fungal biomass increases.

In arid rangeland systems, such as southwestern deserts, fungi pipe scarce water and nutrients to plants.

Credit: Jerry Barrow, USDA-ARS Jornada Experimental Range, Las Cruces, NM. P lease contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

Mushrooms, common in forest systems, are the fruiting bodies made by a group of fungi called basidiomycetes. Mushrooms are "the tip of the iceberg" of an extensive network of underground hyphae.

Credit: Ann Lewandowski, NRCS Soil Quality Institute. P lease contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

Mycorrhizal Fungi in Agriculture

Mycorrhiza is a symbiotic association between fungi and plant roots and is unlike either fungi or roots alone. Most trees and agricultural crops depend on or benefit substantially from mycorrhizae. The exceptions are many members of the Cruciferae family (e.g., broccoli, mustard), and the Chenopodiaceae family (e.g. lambsquarters, spinach, beets), which do not form mycorrhizal associations. The level of dependency on mycorrhizae varies greatly among varieties of some crops, including wheat and corn.

Land management practices affect the formation of mycorrhizae. The number of mycorrhizal fungi in soil will decline in fallowed fields or in those planted to crops that do not form mycorrhizae. Frequent tillage may reduce mycorrhizal associations, and broad spectrum fungicides are toxic to mycorrhizal fungi. Very high levels of nitrogen or phosphorus fertilizer may reduce inoculation of roots. Some inoculums of mycorrhizal fungi are commercially available and can be added to the soil at planting time.

Mycorrhizal fungi link root cells to soil particles sand grains are bound to a root by hyphae from endophytes (fungi similar to mycorrhizae), and by polysaccharides secreted by the plant and the fungi.


THE LIVING SOIL: FUNGI

Fungi are microscopic cells that usually grow as long threads or strands called hyphae, which push their way between soil particles, roots, and rocks. Hyphae are usually only several thousandths of an inch (a few micrometers) in diameter. A single hyphae can span in length from a few cells to many yards. A few fungi, such as yeast, are single cells.

Hyphae sometimes group into masses called mycelium or thick, cord-like &ldquorhizomorphs&rdquo that look like roots. Fungal fruiting structures (mushrooms) are made of hyphal strands, spores, and some special structures like gills on which spores form. A single individual fungus can include many fruiting bodies scattered across an area as large as a baseball diamond.

Fungi perform important services related to water dynamics, nutrient cycling, and disease suppression. Along with bacteria, fungi are important as decomposers in the soil food web. They convert hard-to-digest organic material into forms that other organisms can use. Fungal hyphae physically bind soil particles together, creating stable aggregates that help increase water infiltration and soil water holding capacity.

Soil fungi can be grouped into three general functional groups based on how they get their energy.

  • Decomposers &ndash saprophytic fungi &ndash convert dead organic material into fungal biomass, carbon dioxide (CO2), and small molecules, such as organic acids. These fungi generally use complex substrates, such as the cellulose and lignin, in wood, and are essential in decomposing the carbon ring structures in some pollutants. A few fungi are called &ldquosugar fungi&rdquo because they use the same simple substrates as do many bacteria. Like bacteria, fungi are important for immobilizing, or retaining, nutrients in the soil. In addition, many of the secondary metabolites of fungi are organic acids, so they help increase the accumulation of humic-acid rich organic matter that is resistant to degradation and may stay in the soil for hundreds of years.
  • Mutualists &ndash the mycorrhizal fungi &ndash colonize plant roots. In exchange for carbon from the plant, mycorrhizal fungi help solubolize phosphorus and bring soil nutrients (phosphorus, nitrogen, micronutrients, and perhaps water) to the plant. One major group of mycorrhizae, the ectomycorrhizae (see third photo below), grow on the surface layers of the roots and are commonly associated with trees. The second major group of mycorrhizae are the endomycorrhizae that grow within the root cells and are commonly associated with grasses, row crops, vegetables, and shrubs. Arbuscular mycorrhizal (AM) fungi are a type of endomycorrhizal fungi. Ericoid mycorrhizal fungi can by either ecto- or endomycorrhizal.
  • The third group of fungi, pathogens or parasites, cause reduced production or death when they colonize roots and other organisms. Root-pathogenic fungi, such as Verticillium, Pythium, and Rhizoctonia, cause major economic losses in agriculture each year. Many fungi help control diseases. For example, nematode-trapping fungi that parasitize disease-causing nematodes, and fungi that feed on insects may be useful as biocontrol agents.

Many plants depend on fungi to help extract nutrients from the soil. Tree roots (brown) are connected to the symbiotic mycorrhizal structure (bright white) and fungal hyphae (thin white strands) radiating into the soil.

Credit: Randy Molina, Oregon State University, Corvallis. P lease contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

Fungus beginning to decompose leaf veins in grass clippings.

Credit: No. 48 from Soil Microbiology and Biochemistry Slide Set. 1976. J.P. Martin, et al., eds. SSSA, Madison WI. P lease contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

Ectomycorrhizae are important for nutrient absorption by tree and grape roots. The fungus does not actually invade root cells but forms a sheath that penetrates between plant cells. The sheath in this photo is white, but they may be black, orange, pink, or yellow.

Credit: USDA, Forest Service, PNW Research Station, Corvallis, Oregon. P lease contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

The dark, round masses inside the cells of this clover root are vesicules for the arbuscular mycorrhizal fungus (AM).

Credit: Elaine R. Ingham. P lease contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

Where Are Fungi?

Saprophytic fungi are commonly active around woody plant residue. Fungal hyphae have advantages over bacteria in some soil environments. Under dry conditions, fungi can bridge gaps between pockets of moisture and continue to survive and grow, even when soil moisture is too low for most bacteria to be active. Fungi are able to use nitrogen up from the soil, allowing them to decompose surface residue which is often low in nitrogen.

Fungi are aerobic organisms. Soil which becomes anaerobic for significant periods generally loses its fungal component. Anaerobic conditions often occur in waterlogged soil and in compacted soils.

Fungi are especially extensive in forested lands. Forests have been observed to increase in productivity as fungal biomass increases.

In arid rangeland systems, such as southwestern deserts, fungi pipe scarce water and nutrients to plants.

Credit: Jerry Barrow, USDA-ARS Jornada Experimental Range, Las Cruces, NM. P lease contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

Mushrooms, common in forest systems, are the fruiting bodies made by a group of fungi called basidiomycetes. Mushrooms are "the tip of the iceberg" of an extensive network of underground hyphae.

Credit: Ann Lewandowski, NRCS Soil Quality Institute. P lease contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

Mycorrhizal Fungi in Agriculture

Mycorrhiza is a symbiotic association between fungi and plant roots and is unlike either fungi or roots alone. Most trees and agricultural crops depend on or benefit substantially from mycorrhizae. The exceptions are many members of the Cruciferae family (e.g., broccoli, mustard), and the Chenopodiaceae family (e.g. lambsquarters, spinach, beets), which do not form mycorrhizal associations. The level of dependency on mycorrhizae varies greatly among varieties of some crops, including wheat and corn.

Land management practices affect the formation of mycorrhizae. The number of mycorrhizal fungi in soil will decline in fallowed fields or in those planted to crops that do not form mycorrhizae. Frequent tillage may reduce mycorrhizal associations, and broad spectrum fungicides are toxic to mycorrhizal fungi. Very high levels of nitrogen or phosphorus fertilizer may reduce inoculation of roots. Some inoculums of mycorrhizal fungi are commercially available and can be added to the soil at planting time.

Mycorrhizal fungi link root cells to soil particles sand grains are bound to a root by hyphae from endophytes (fungi similar to mycorrhizae), and by polysaccharides secreted by the plant and the fungi.


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