[2] This species is recognised by its pale, thick, smooth, areolate thallus that contains hypostictic acid as a major metabolite, and its large apothecia (fruiting bodies) that are distinctively adorned with a whitish inner collar in immature stages.

[1] The thallus of Rhizocarpon torquatum is crustose and epilithic, forming colonies approximately 1–4 cm (0.4–1.6 in) wide, varying in colour from greyish white to pale grey with a greenish tint.

[1] Apothecia (fruiting bodies) are numerous, ranging from 0.52 to 1.30 mm in diameter, with a margin that can be thick and varies from being the same as the blackish disc to considerably paler.

It grows on seasonally inundated, siliceous rocks within the river bed, an environment that also supports a diverse range of other rock-dwelling lichen species adapted to periodic disturbances.

These species include: Paraporpidia leptocarpa, Baeomyces heteromorphus, Trapelia coarctata, Stereocaulon ramulosum,Hymenelia lacustris, and the only known locality of Porina australis.