Water Molds and Simple Fungi Oomycota, Chytridiomycota, Zygomycota EKU General Botany Lab

Saprolegnia (Oomycota) oogonium with eggs inside antheridial hyphae vegetative hyphae (2n and coenocytic)

Saprolegnia reproduction Sexual Asexual Zoosporangium (resistant zygote) (Antheridia and antheridial hyphae are basically interchangeable terms.)

Phlyctochytrium mycelia a ‘holocarpic’ chytrid rhizoidal hyphae

Allomyces a filamentous chytrid coenocytic hyphae Is this the sporophyte (2n) phase, or the gametophyte (n) phase? resistant sporangia (meiosporangia) mitosporangia The true colors of this organism have been greatly distorted by the technique used to make the permanent slide from which this photo was taken. (See the next slide.)

The last slide was of preserved material. Here is a better slide--of living material. This is the diploid (2n) phase of Allomyces. All of the sporangia in this photo are resistant meiosporangia. No thin-walled mitosporangia are visible. These resistant sporangia eventually will detach and float to the bottom. As spring arrives, meiosis will occur inside the sporangia and they will release haploid (n) meiozoospores. photo by Ross Clark

Allomyces gametangia In Allomyces, the male and female gametangia usually occur in pairs, with one sex above the other. In the picture above, you can see the brownish male gametangia above the clear female gametangia. The female gametangia have already released their gametes. The bright white spots are the exit papillae where the female gametes left the gametangia. photo by Ross Clark

Rhizopus nigricans (Zygomycota) Black Bread Mold Mycelium (coenocytic) Sporangium Columella Sporangiophores Rhizoids Spores

Rhizopus nigricans reproduction (Zygomycota) suspensor asexual phase sexual phase diploid

Some chytrid pictures chytrid on diatom a holcentric chytrid More chytrids! Polymyxa, a chytrid-like organism, but not a chytrid (has 2 anterior whiplash flagella) Diagram of chytrid zoospore; one posterior whiplash flagellum chytrids on spirogyra cell Don’t forget – some chytrids, such as Allomyces, have filamentous hyphae.