PARTS OF THE FUNGUS AND THEIR CHARACTERISTICS - BIOLOGY - 2025

The parts of the fungus can be divided into the external and internal Fungi are the eukaryotic organisms that comprise the Kingdom Fungi. They are living beings made up of cells that are covered by a protective wall, as well as plants (although of different composition), but that lack photosynthetic capacity (they are heterotrophs) and store glycogen, as well as animal cells.

More than 100,000 species of fungi have been described in nature, including some unicellular organisms, such as the yeasts used to grow bread or produce beer, and other multicellular ones, such as mushrooms and truffles, for example.

Diagram of the parts of an Amanita caesarea mushroom. Arturo D. Castillo (Zoram.hakaan) / CC BY (https://creativecommons.org/licenses/by/3.0)

Fungi are very particular organisms, not only from the cellular point of view, but also in relation to their habitat and nutrition: they generally develop better in environments with high humidity and grow on organic matter, on which they feed by secreting digestive enzymes. and absorb the nutrients that they release (they are decomposers).

Photograph of a Xerocomellus engelii mushroom (Source: Przykuta via Wikimedia Commons)

Mycologists, who are the scientists in charge of the study of fungi, have classified them mainly with respect to certain characteristics of their life cycles and their morphology, so that today we recognize four different phyla: Chytridiomycota, Zygomycota, Ascomycota and Basidiomycota.

Although the members of each of these phyla can be considerably different from each other, the "basic" structure of these is more or less equivalent, so they share many of their anatomical characteristics, with their respective differences or modifications.

Parts of a mushroom and their characteristics

Hypha (1), Conidiophore (2), Phialis (3), Conidia (4), Septa (5)

Fungi have a fairly simple organization compared to other organisms such as plants or animals. With few exceptions, most fungi are multicellular organisms made up of long filaments known as hyphae.

- The hyphae

The hyphae are generally branched and may be septate or non-septate. Those hyphae that do not have septa, partitions or internal transverse walls, are coenocytic, since the same cytosol houses multiple nuclei.

In septate hyphae, on the contrary, the existence of internal transverse walls separates the filament into cells (with one or more nuclei) that are relatively individual, since the "septa" (said walls) have a central pore through which mobilizes a large part of the cytosolic content, including small organelles and even nuclei, in some cases.

Hyphae always grow apically, that is, at one end, and their cell walls are tubular and extremely thin. They can be colorless, hyaline, or very colorful like red, green, yellow, orange, or black.

Photograph of the hyphae of a fungus (Source: Carlos mj93 via Wikimedia Commons)

In addition, in a fungus there can be three types of hyphae, namely:

Somatic hyphae

They are what make up the mass or main body of the fungus. These can be:

• Stoloniferous, if they grow with an inclination parallel to the substrate.
• Rhizobial, if they work in fixing the fungus to the substrate.
• Sporangiophores, if they are the ones that support spore-producing sporangia.

Haustorial hyphae

They have only been observed in parasitic fungi, who use them to absorb nutritional substances from the interior of the cells of their hosts.

Reproductive hyphae

These are those that participate in sexual reproduction, such as the ascogenic hyphae (which generates the meiotic asci of the ascomycetes) and the basidiogens (which generates the basidia or exogenous spores of the basidiomycetes).

Other authors use a somewhat different classification of hyphae, distinguishing three categories: generative hyphae, skeletal hyphae (classical and spindle-shaped) and binding hyphae.

- The mycelium

In all multicellular fungi, the hyphae are "organized" in a complex tangle or network that is called the mycelium. The same fungus can have one or more types of mycelia, which form as it undergoes the phases of its life cycle.

Some authors describe the mycelium as the vegetative portion of the fungus and in many cases it can be seen with the naked eye, without the need to use a special device; in such cases, the mycelium is organized to form the fruiting body, which is present mainly in ascomycetes and basidiomycetes.

Photograph of the mycelium of a mushroom (Source: Rob Hille via Wikimedia Commons)

As a vegetative portion, the mycelium of a fungus can also function in its asexual reproduction by fragmentation, for the production and dispersal of new clonal individuals.

- Fruiting body

The fruiting body is the structure that comes to mind easily when we imagine a mushroom in the wild without much effort. This structure is made up of different parts:

Stem

çAlso called "stipe" or "foot", the stem is made up of hyphae derived from vegetative growth and is responsible for supporting the cap or crown of the fruiting body.

Volva or basal cup

It is a membrane that covers the fruiting body when it is just beginning to grow. When the fruiting body grows and fully develops, the remains of the membrane remain at the base of the stem. It is only present in some types of fungi.

Stem ring

It is observed in some species of fungi and it is the rest of another membrane different from the volva that is responsible for protecting the spores when they are immature. It is generally observed in a few species of fungi.

Foils and lamellae

Also called cells and cells, they correspond to the place where the morphogenesis of the basiodiospores occurs. Interspersed with the basidiospores are sterile hyphae called "cystidia." The lamellae are found under the cap, forming the union between it and the stem.

Amanita muscaria, poisonous mushroom.

Hat, pileus or pileus

In the lower part of this are the laminae and lamellae (the hymenium) and, therefore, the basidiospores. It is the most striking part of the fruiting body of the "higher" fungi and consists of the "aerial" end of the fruiting body.

This structure is believed to be an adaptation of fungi to achieve a greater dispersal of their spores. Hats can vary in colors, shapes, sizes, composition, and hardness.

Fungi Kingdom Edge Honors

The organization of hyphae and mycelia in the Fungi Kingdom can be highly variable, so it may be prudent to make some distinctions between the most representative organisms of the four phyla that compose it: Chytridiomycota, Zygomycota, Ascomycota and Basidiomycota.

Chytridiomycota

Chytridiomycetes are the only fungi that produce flagellated gametic cells during sexual reproduction. This group includes organisms composed of spherical cells or coenocytic hyphae with few transverse septa.

Many of the chytridiomycetes produce branched rhizobial hyphae that help them sustain themselves from the dead organisms on which they feed. These are macroscopic fungi, that is, visible to the naked eye, but do not produce recognizable fruiting bodies.

Zygomycota

Mushroom of the genus Mucor, of the Zygomycota group. By Photo Credit: Content Providers: CDC / Dr. Lucille K. Georg, via Wikimedia Commons

Zygomycetes form coenocytic hyphae and live, above all, on dead or decomposing organic matter such as manure (they are coprophiles). Some are internal symbionts of the digestive tract of animals and others are of some plants (mycorrhiza). These fungi produce spores, so they have somatic hyphae of the sporangiophore type.

Ascomycota

Ascomycete diversity

Ascomycetes produce septate hyphae with perforated septa and live mainly on dry land. To this group belong many fungi that have fruiting "cup" bodies called ascocarpus.

In addition, they also include yeasts (which are single-celled fungi), various types of molds that grow on food, and edible fungi such as truffles and morels.

Basidiomycota

Photograph of the basidiomycete Galerina marginata (Source: Pethan via Wikimedia Commons)

The basidiomycetes are perhaps the most representative fungi of the Fungi Kingdom, since the mushrooms found both in warehouses and in the field belong to this group. The mushrooms correspond to the fruiting body of these fungi and fulfill a reproductive function.

A mushroom, also known as a basidiocarp or basidioma, is a fruiting body that protrudes from the surface of the soil (in which there is also a large and extensive mycelium) and that corresponds to one of the phases of the life cycle of these fungi.

References

1. Carlile, MJ, Watkinson, SC, & Gooday, GW (2001). The fungi. Gulf Professional Publishing.
2. Lindorf, H., Parisca, L., & Rodríguez, P. (1991). Botany. Central University of Venezuela. Library Editions. Caracas.
3. Nabors, MW (2004). Introduction to botany (No. 580 N117i). Pearson.
4. Raven, PH, Evert, RF, & Eichhorn, SE (2005). Biology of plants. Macmillan.
5. Solomon, EP, Berg, LR, & Martin, DW (2011). Biology (9th edn). Brooks / Cole, Cengage Learning: USA.