The Fungi (key terms)

Hypha (hyphae)

long, branching filaments that make up the structure of fungi, oomycetes, and actinobacteria. They are the primary way that most fungi grow vegetatively, and when grouped together, they are called a mycelium.

Mycelium (mycelia)

a root-like structure of a fungus that's made up of a network of thin fungal strands called hyphae. It can be found in soil, inside plants and animals, and under the reproductive structures of fungi.

Haustorium (Haustoria)

a root-like structure that absorbs nutrients and water from another structure, such as a plant or fungus. Haustoria are formed when a specialized fungal hypha or parasitic plant root or stem penetrates the host's tissues.

mycorrhizae

fungi that have a symbiotic relationship with the roots of many plants. The fungi which commonly form mycorrhizal relationships with plants are ubiquitous in the soil.

arbuscule

a symbiosis between plants and members of an ancient phylum of fungi, the Glomeromycota, improves the supply of water and nutrients, such as phosphate and nitrogen, to the host plant.

ascomycota

Ascomycota or Endomycopsis, is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species.

basidiomycota

Basidiomycota is one of two large divisions that, together with the Ascomycota, constitute the subkingdom Dikarya within the kingdom Fungi. Members are known as basidiomycetes.

basidium

a microscopic structure that produces spores and is found on the fruiting body of basidiomycete fungi, such as mushrooms and toadstools

basidiospore

reproductive spores produced by many fungi, including mushrooms, rusts, smuts, and shelf fungi. They are typically oval-shaped and hyaline, and can be colorless or pigmented.

basidiocarp

a fruiting body that produces spores and is characteristic of the hymenomycetes group of fungi. Basidiocarps are also known as basidiomes or basidiomata.

gills

also called basidia (singular basidion), and they form and protect the reproductive cells of the mushroom. Because the mushroom is the reproductive body of the larger fungus organism, we also call mushrooms fruiting bodies.

cap

the spore-producing part of a mushroom that protects the hymenium, or spore-bearing surface. The pileus is a characteristic feature of agarics, boletes, tooth fungi, some polypores, and some ascomycetes.

stipe

the stem or stalk-like feature supporting the cap of a mushroom. Like all tissues of the mushroom other than the hymenium, the stipe is composed of sterile hyphal tissue. In many instances, however, the fertile hymenium extends down the stipe some distance.

mating type (+) or (-)

often designated as "+" and "-" to differentiate between different strains of organisms that are compatible in sexual reproduction. Mating types are similar in morphology, making them difficult to distinguish.

dikaryotic (n+n)

a condition in fungi where a cell contains two separate haploid nuclei, meaning each nucleus has only one set of chromosomes, resulting in a "n + n" representation and signifying a dikaryotic stage during sexual reproduction; essentially, the cell has two nuclei per cell, but they haven't fused yet, maintaining distinct genetic information from each parent.

plasmogamy

a stage in the sexual reproduction of fungi where the protoplasm of two parent cells fuse, but the nuclei do not. This process results in two haploid nuclei in the same cell, forming a dikaryon.

kayogamy

the process where two haploid nuclei from different parent cells fuse together during sexual reproduction, creating a diploid nucleus, essentially the final step in the fusion of two cells where their genetic material combines; it occurs after plasmogamy (cell membrane fusion) and is followed by meiosis.

lichen

refers to the fungal component of a lichen, which is a symbiotic organism composed of a fungus (the "mycobiont") living in close association with an alga or cyanobacteria (the "photobiont") where the fungus provides protection and structure while the alga or cyanobacteria provides food through photosynthesis; essentially, a lichen is not just a fungus, but a partnership between a fungus and another organism.