Fungi

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Ascomycetes

  • Peziza asci with ascospores x400.
  • Physica x40. A cup fungus sexual structure growing on the bark of a dead tree.
  • Venturia inequalis perithecium x100. This ascus bearing structure is shown on a cross section of a crab apple leaf.
  • Saccaromyces (baker's yeast) x1000. These are single celled ascomycetes that often reproduce asexually by budding. This can be seen in some of the yeast cells near the center of the illustration.

    Basidiomycetes

  • Corpinus basidia with basidiospores x1000. This is the gill of a mushroom. Two basidia are shown, each with 4 basidiospores attached externally by little stalks.
  • Puccinia (wheat rust) aecia and pycnia x40. This is a cross section of a barberry leaf showing two stages of this fungus's complex life cycle. Aeciospores are on the upper surface and pycniospores on the lower surface. Pycniospores will infect wheat plants.
  • Puccinia uredia x40. The illustration shows a wheat stem with the bases of two leaves wraped around it. The leaves have groups of uredospores on their surfaces. These spores can blow around and infect other wheat plants.
  • Puccinia uredospores on wheat leaves x100. The red color of these spores is the basis of the name "wheat rust".
  • Puccinia teliospores x100. These two celled wheat rust spores form at the end of the growing season. They fall to the ground and overwinter there. In the spring the spores germinate on the ground, produce a basidium, and the resulting basidiospores infect barbarry plants.
  • Ustilago maydis (corn smut) x40. Part of a greatly distorted corn seed that is infected. The red areas are clusters of fungal spores.
  • Ustilago maydis spores inside corn. x400.

    Zygomycetes

  • Rhizopus (bread mold) hyphae x100. Unlike the ascomycetes and basidiomycetes, the hyphae of the zygomycetes is coenocytic. That means that there are few or no partitions dividing the hyphae into individual cells.
  • Rhizopus asexual sporangium x100. You can see several coenocytic hyphae, one of which ends in a sporangium.
  • Rhizopus asexual spores in sporangium x400. Several nuclei crowd into the end of a hypha. A septum forms (one of the few in the otherwise coenocytic hyphae) forming a sporangium and separating these nuclei from the rest of the hypha. Each nucleus then becomes a haploid asexual spore.
  • Rhizopus zygospore x100. This diploid (2N) spore is fromed from the fusion of two nuclei, one each from two sexually compatible hyphae. Look carefully inside the spore and you can see the diploid nucleus. This spore, with its thick coat, can survive draught cold and lack of food. When conditions improve the spore germinates, meiosis occurs and the spore grows an asexual sporangium full of haploid spores.

    Imperfect fungi (Deuteromycetes)

  • Aspergillus x400 showing the swolen end of the hypha that bears chains of conidiospores.
  • Chains of Aspergillus conidiospores x400.
  • Penecillium x1000. The distinctive finger-like chains of conidiospores are shown.

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