Basidiocarps (fruit bodies) are gelatinous, lobed to foliose (leaf-like) and appear to be parasitic on ascomycetous fungi on wood.

[1] The species was originally described from Indonesia, but has been reported from elsewhere in Asia and also in Australia and North America.

Sirobasidium magnum was described from Borneo and Java in 1934 by Dutch mycologist Karel Boedijn.

[1] Sirobasidium magnum was originally described on rotten wood, but is possibly parasitic on fungi in the genus Hypoxylon growing on dead attached or fallen wood.

[1] Sirobasidium magnum has been recorded from Asia (China,[3] Indonesia,[2] Japan,[4] Korea,[5] Malaysia,[6] Philippines,[4] Singapore,[7] Taiwan,[1] Thailand[8]), Australia,[7] the Seychelles,[7] Tahiti,[9] and North America (USA).