Slime moulds

Slime moulds are curious organisms that long defied categorization. They used to be considered fungi, because most species are associated with soil or decomposing wood, where they are either saprobic or feed on bacteria.

Their life cycles include a “fruiting body” stage which is the product of sexual reproduction. The spores released develop into amoeboid organisms, which either form multinucleated plasmodia large enough to be visible to the naked eye (plasmodial slime moulds) or individual small amoebae which swarm and aggregate into a multicellular slug which eventually forms the fruiting body (cellular slime moulds). Some of the life cycle stages may be amoebo-flagellates, i.e. flagellated cells which are also capable of amoeboid motion.

Unlike most of the other protists on this website, slime moulds don’t necessarily require a microscope for appreciation. Patience and a keen eye are necessary to spot them among the leaf litter and decaying wood in a forest, however.

A checklist of Southeast Asian cellular slime moulds was published in 1976 (JC Cavender, American Journal of Botany 63 (1): 60-70 and 71-73), and updated recently by WC Rosing and colleagues (2009, “Corticolous Myxomycetes of Singapore.” Gardens’ Bulletin Singapore 61 (1): 151-158, and WC Rosing, DW Mitchell, G Moreno, SL Stephenson (2011) “Additions to the Myxomycetes of Singapore.” Pacific Science 65 (3): 391-400.)

Plasmodial slime moulds

“Scrambled egg” slime mould

The plasmodium of this slime mould has come to the surface of the piece of decaying wood that it has presumably been occupying. The bright yellow color and lumpiness seem to warrant it being called a “scrambled egg slime mould”. Found in forested area in Upper Bukit Timah, near a freshwater stream.

Reticulate plasmodium

Net-like veins of a slime plasmodium. Photograph courtesy of Serena Lee.

Slime mould fruiting bodies

These samples were collected from various forested localities around Singapore, and were mostly found on decaying wood or leaves in the leaf litter. These photographs are provided by kind courtesy of Serena Lee, Singapore Botanic Gardens. A short article was featured in the Gardens’ newsletter, Gardenwise (pdf).

Most of these species have not been identified. If you know any of them, leave a comment!

Arcyria denudata

Arcyria magna

Cribraria sp.

Diachea leucopodia

Note the iridescence on the otherwise-black fruiting body itself.

Hemitrichia calyculata

Physarella oblonga

cf. Physarum

Unidentified white fruiting bodies

Unidentified yellow fruiting bodies

Unidentified green fruiting bodies

Unidentified red fruiting bodies

Unidentified brown or black fruiting bodies


One Response to Slime moulds

  1. Joe says:

    What beautiful and fascinating organisms!

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