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A slime mould - Arcyria denudata

In the vicinity of a large man-made mound (NS3977 : Mound beside the River Leven), a damp log was host to five different species — Link — of slime mould.

Arcyria denudata is the vivid reddish species shown at the centre and in the right-hand side of the photo. The spore-producing structures (sporangia) form the rather fluffy-looking structures shown in this photo; microscopically, they can be seen to consist of threads called "elaters" (elaters also occur in liverworts: NS3878 : A liverwort - Pellia epiphylla); these threads change their shape in response to changing humidity, and so serve to push out spores when conditions are suitable.

The small shiny black spheres in the left-hand side of the photo also belong to a slime mould, but to a quite different species: NS3977 : A slime mould - Metatrichia floriformis. Slime moulds cannot, in general, be identified by their naked-eye appearance alone, or (even worse) from photos alone; in many cases, microscopic examination is required (specimens of the two species shown here were examined at home).

[The photo was taken during the season when a large number of slime moulds can generally be found, but the weather of the preceding few months probably accounted for their particular abundance when this photo was taken. According to the textbooks, a good time to search for slime moulds is after a few dry days following a prolonged period of rain. The photo was taken after a few dry days following one of the wettest summers ever recorded for this area (on that topic, compare NS3977 : Cyanobacteria - Nostoc commune).]

For another Arcyria species, which forms considerably larger structures, see: NS3878 : A slime mould - Arcyria nutans.

[NB: Slime moulds are not strictly fungi.]