Water Molds and Simple FungiOomycota, Chytridiomycota, Zygomycota

EKU General Botany Lab

Saprolegnia (Oomycota)

oogonium witheggs inside

antheridialhyphae

vegetative hyphae(2n and coenocytic)

Saprolegnia reproductionSexual Asexual

Zoosporangium

(resistant zygote)

(Antheridia and antheridial hyphae arebasically 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?

resistantsporangia(meiosporangia)

mitosporangia

The true colors of this organism have beengreatly distorted by thetechnique used to make the permanent slide fromwhich this photo wastaken. (See the nextslide.)

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 springarrives, 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 sexabove the other. In the picture above, you can see the brownish male gametangia abovethe 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

suspensor

asexual phase

sexual phase

diploid

Some chytrid pictures

chytrid ondiatom

a holcentric chytridMore chytrids!

Polymyxa, a chytrid-like organism,but not a chytrid (has 2 anteriorwhiplash flagella)

Diagram of chytridzoospore; one posteriorwhiplash flagellum

chytrids on spirogyra cell

Don’t forget – some chytrids, such as Allomyces, have filamentous hyphae.