The type specimen was collected on Madeira (Portugal), south of the Ribeira da Janela, at an elevation of 1,225 m (4,019 ft).

[1] The lichen has a foliose (leafy) thallus that is bright green (when wet) to olive brown (when dry), measuring up to 15 cm (6 in) in diameter and comprising oblong lobes.

Apothecia occur infrequently in this species; when present, they are usually situated along the lobe edges or along upper surface ridges, and are reddish-brown with an entire margin.

[1] A real-time polymerase chain reaction assay has been developed that will distinguish between Lobaria pulmonaria, L. immixta and L. macaronesica.

[2] Lobaria macaronesica grows as an epiphyte on trees and shrubs found in subtropical laurel forests, including Laurus azorica, Persea indica, Pittosporum coriaceum, Vaccinium cylindricum, Myrica faya, Ilex canariensis, and Erica arborea.