Lecanora helmutii is a rare species of corticolous (bark-dwelling), crustose lichen in the family Lecanoraceae.

The type specimen was collected from the eastern side of Stanley Highway, where it was found growing on the bark of Banksia marginata in a coastal swampy woodland dominated by Melaleuca.

Other associated lichens include Austroparmelina pseudorelicina, Bactropsora paludicola, Menegazzia subpertusa, Pannaria elixii, and Parmotrema perlatum.

[1] Characteristics of the lichen, including biatorine apothecia (consisting of only a pale, not carbonized proper margin and always lack a thalline margin), Lecanora-type asci, and simple, translucent ascospores, place it in the Lecanora symmicta species group within the genus Lecanora.

It contains usnic acid and zeorin as lichen products; all standard chemical spot tests on the thallus are negative.