A blob of fungus?

This post is also available in: Dutch.

Weird foamy thing in our front garden.

Suddenly, from one day to another, it was there. A little yellow sponge that was stuck to a piece of rotting wood. Our love for nature in general and mushrooms in particular has triggered the decision to leave our yard and driveway as natural as possible. Enough green, both large and small trees, herbs, and room for fallen leaves and dead branches of trees to decompose. After a little rainfall the soil stays moist, the leaves and wood rot and provide an ideal breeding ground for fungi which are enthusiastically showing their reproductive organs in the form of mushrooms.

Slimy mold

The yellow sponge was not there the day before, and it was therefore right in the spotlight on the dark brown wet wood. It looked like a piece of egg thrown up by someone, oddly shaped and with a dark red drop in the middle. It looked suspiciously like a fungus and with our camera in hand, we  took the opportunity to shoot an entire photo series.
With the first book on mushrooms that we opened, we immediately struck gold on the first page.  The little sponge-like organism was in there and it was described as a slime fungus. With the help of Internet it soon became clear that the description in the book was outdated, not surprisingly since the book was written in 1973. At first the sponge was considered to be part of the Kingdom of Mushrooms, in Latin called Fungae, but now it is considered not to be part of this Kingdom anymore but part of the Kingdom of Amoebozoa.


Fungae are eukaryotic organisms, which means that the cells of these organisms contain complex structures enclosed in a cell membrane. Every little cell is enclosed in a type of ‘skin’. Amoebozoa are, what the word suggests, amoeba-like organisms whose individual cells are indistinguishable. In nature they occur as a plasmodium, a blob of fluid or protoplasm without cell membranes to separate the cells and only one external membrane to keep everything inboard. By the way, it seems that the cult movie “The Blob” is based on these organisms. In this horror film ‘The Blob’ comes to Earth from space and then the thing starts eating people.
Slime Molds, as they are called, feed on bacteria and even do so in an amoeba-like manner by ingesting them (draping themselves around and over the food) and then taking it up and digesting it. ‘Real’ mushrooms do have cell membranes and externally digest their food by secreting enzymes  before ingesting the then dissolved food.
The whitish “egg-white” in the photo is the plasmodium of the species, the part that lives until it is time to reproduce, and the yellow sponge is merely the fruiting body where spores are formed. It is difficult to find information on the red drop, it seems to be the liquified tissue of the organism itself.

Dog Vomit Slime Mold

It is still guess work to identify the exact species, but after researching different websites from fungae and mold experts the identification process seems to result in the name Fuligo septica or in rough English, “Dog Vomit Slime Mold”, because some say it looks like dog vomit. In Dutch a name is used which is a little more lovable which is the Witch’s Butter or Heksenboter. The species occurs throughout the world and loves to establish itself between decaying wood where it is moist enough and where there are enough bacteria to prey upon as a food supply. In tropical regions they are also frequently found high up in trees.
The most bizarre thing about the Dog Vomit Slime Mold is the fact that the organism moves by using the slimy white translucent plasmodium. If you would look at the organism for about a minute you can even watch the movement, which can even reach speeds of up to 1.35 mm per second. The movement is caused by the constant movement of the cytoplasm, the fluid in the body, from front to back and back again.

Most fungi of the island are not even close to being identified yet. Whether they do or do not belong to the kingdom of Fungae and are or are not real mushrooms, they remain mysterious organisms that suddenly appear out of nowhere and just as quickly disappear to the naked eye. It is certainly worth to keep your eyes open and admire them when possible.

About Michelle da Costa Gomez