Stigmatodactylus sikokianus (Orchidaceae) mainly acquires carbon from decaying litter through association with a specific clade of Serendipitaceae.

Mycorrhizas usually engage in mutualism, in which soil fungi contribute minerals to plants that in turn supply photosynthetically fixed carbon (C) to their fungal partners (Smith & Read, 2008). However, the functional status of such symbioses in orchids remains somewhat controversial.