Another world ...
Although their appearance might suggest that slime moulds are fungi, they are neither fungi nor moulds; though they often form spore-bearing structures that resemble those of true fungi. Most slime moulds are generally deemed by taxonomists to be protists; the oddities of the natural world that don't seem to fit in with the rest of our global taxonomic grouping system - though this classification is still open to some debate.
Although many species fruit on decaying wood, they do not form penetrating and absorptive masses of hyphae in the woody substrate. Instead, slime moulds form structures called plasmodia, which are naked [i.e. without cell walls] masses of protoplasm [a colourless material comprising the living part of a cell], which can move about and engulf particles, in an amoeboid-like manner, in order to maximize the nutrients they can draw from their food source. The plasmodia creep about over the surfaces of resources, consuming bacteria, fungal spores, plants, protozoa, and small particles of non-living organic matter. When conditions become unfavorable the plasmodia convert into spore-bearing structures known as sporangia [clusters of spores]. Spores from the sporangia are then dispersed to new habitats and the life cycle begins once again. The young sporangia, of what I believe to be Tubulifera arachnoidea, formerly Stemonitis ferruginosa, is pictured above living on a heavily decayed beech tree; this particular mass having a diameter of no more than 10mm.
Slime moulds are strange and wonderfully varied in appearance. When magnified through the eye of a macro lens another world is entered …
O’Reilly, P. (2016). Fascinated by Fungi – exploring the majesty and mystery, facts and fantasy of the quirkiest kingdom on earth. Llandysul: First Nature, pp.78-79.
Sterry, P. and Hughes. B. (2009). Collins Complete Guide to British Mushrooms and Toadstools. London: HarperCollins, p. 334-335.