Overview of the "true" Fungi

Outline

Introduction to the "true fungi"

Zygomycota
a.k.a. zygomycetes

Characteristics

those of fungi in general (see previous page)

coenocytic hyphae

morphology of mycelium

characteristic life cycle (see below)

Ascomycota

a.k.a. ascomycetes

largest phylum

Characteristics

general fungal characteristics

conidiophores produce conidia (asexual spores)

hyphae are septate (and perforated)

charactersitic life cycle (see below)

Basidiomycota

a.k.a. basidiomycetes

16,000 spp in 3 classes:

  • Hymenomycetes (mushrooms, bracket fungi, etc.)
  • Gasteromycetes (puffballs, stinkhorns)
  • Teliomycetes (smuts & rusts)

Characteristics

general fungal characteristics

also make various asexual spores

hyphae are septate and perforated, with parenthosomes (except in Teliomycetes)

characteristic life cycle (see below)

Fungal life cycles

Zygomycete life cycle
Asexual:
produce sporangiospores in sporangia on the ends of sporangiophores

Sexual:

click here to see life cycle diagram

may be heterothallic or homothallic

Ascomycete life cycle

Asexual:
conidiophores produce conidia

Sexual:

  1. haploid mycelium produces ascogonia and antheridia
  2. ascogonium produces trichogyne
  3. plasmogamy, with exended dikaryotic phase
  4. out of ascogonium grows dikaryotic ascogenous hyphae
  5. with sterile haploid hyphae forms an ascoma (fruiting body)
  6. asci are produced (among paraphyses) in the hymenium of the ascoma
  7. after karyogamy and meiosis, 8 ascospores (sexual spores) are produced in each ascus

    kinds of ascomata:

    • none (naked asci)
    • apothecium (cup)
    • perithecium (flask)
    • cleistothecium (closed)

Basidiomycete life cycle

Asexual:
various asexual spores are produced

Sexual (for Hymenomycetes and Gasteromycetes):

  1. in haploid mycelium (primary mycelium), two hyphae fuse
  2. plasmogamy, with exended dikaryotic phase (secondary mycelium)
  3. dikaryotic mycelium produces basidioma
  4. basidia are produced on hymenium of basidioma
  5. karyogamy and meiosis take place in basidia, producing 4 haploid nuclei
  6. 4 basidiospores made, each on the end of a sterigma
  7. basidiospores pop off, wind disperse, and germinate into new monokaryotic hyphae

Diversity

Hymenomycetes (bear spores on surface of basidioma)
mushrooms, toadstools (hymenium on gills)
basidium anatomy (pileus, stipe, annulus)

boletes, most bracket fungi (hymenium on pores)

coral fungi (hymenium on "teeth")

Gasteromycetes (bear spores inside basidioma)

basidium anatomy (gleba and peridium)

puffballs, earthstars, stinkhorns, bird's nest fungi

Teliomycetes (produce basidia on a sorus)

rusts and smuts

e.g., Puccinia graminis (black rust of wheat)

Deuteromycota

Introduction
a.k.a. deuteromycetes, imperfect fungi, fungi imperfecti

an artificial taxon (polyphyletic)

Characteristics

lack sexual stage

many are probably ascomycetes, since they form conidia

others are sygomycetes or basidiomycetes that have lost sexual reproduction

 

Vocabulary

click here to go to "true" fungi vocabulary


on to the next topic -- fungal ecology and economic importance!

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