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Aero-aquatic fungi

Posted: Mon Nov 27, 2017 9:51 pm
by Chris Yeates
I am always keen to point out to mycologists with access to a microscope that there are other areas to have a go at as well as the toadstools - for a start it helps to be able to study fungi all-year long if one has several strings to ones myco-bow. Also access to literature is much better now (and I may be able to help anyone interested in that respect).

Ingoldian fungi may be familiar to some on this site - see: for further info (including a link to a PDF which gives a key with drawings to most of the species encountered.

A recent collection (see below) has made me think of another ecological group (it is important to appreciate that these fungi may not be taxonomically closely related) - the aero-aquatic fungi. There is a good overview here:

"If leaves and twigs from the mud surface of stagnant pools or slow-running ditches are rinsed and incubated at room temperature in
a humid environment (e.g. a Petri dish or plastic box lined with wet blotting paper), fungi with very characteristic large conidia usually develop
within a few days. The common feature of the conidia of these fungi is that they trap air as they develop, which assists in floating off the conidia
if the substratum is submerged in water. Conidia of this type have been termed bubble-trap propagules.
Such fungi grow vegetatively on leaves and twigs, often in water with quite low amounts of dissolved oxygen. Under submerged condi
tions these fungi do not sporulate, but do so only after incubation under aerial conditions in which a moist interface between air and water
is provided, as might happen at a pond margin as the water dries up and previously submerged twigs or leaves become exposed to air. They have
therefore been termed aero-aquatic fungi.

The bubble-trap propagules of aero-aquatic fungi are hydrophobic and float ungerminated at the water surface of stagnant ponds. Autumn
shed leaves which fall onto the water are rapidly colonized. The leaves eventually sink to the bottom of the pond and growth of the fungi continues so long as dissolved oxygen is available in the water

Following a prolonged period of submersion under the anaerobic or near-anaerobic conditions of the bottom silt of a pond, it takes several
days for sporulation of aero-aquatic fungi to commence in air. Incubation in well-aerated water before exposure to air improves the
recovery, suggesting that a period of aerobic growth is a stimulus to sporulation. For most species studied, exposure to light also enhances
sporulation." John Webster "Introduction to Fungi", 3rd edition (1907).

You can see the "bubble-trap" conidia in the image at top right of the image of Helicodendron conglomeratum 'plate' where they are shown in optical section; also in the clusters of living conidia in water of Helicodendron triglitziense. In addition many of these fungi are rather beautiful:
Helicodendron triglitziense 0a.jpg
Helicodendron conglomeratum 0a.jpg

Re: Aero-aquatic fungi

Posted: Mon Nov 27, 2017 11:25 pm
by Flaxton
I don't have enough hours in the day already without looking at these, but they do look tempting ;)

Re: Aero-aquatic fungi

Posted: Tue Nov 28, 2017 1:14 am
by Chris Yeates
Flaxton wrote:
Mon Nov 27, 2017 11:25 pm
I don't have enough hours in the day already without looking at these, but they do look tempting ;)
You are of course excused Mal - but there may be others? And on a site like Strensall you can bet your boots they are there aplenty . . .