Spjut & Hale) that grow on rocks (saxicolous) and soil (terricolous), is distinguished by a relatively thick crusty cortex (like a dry pie crust) overlying a medulla with rigid lattice of hyphae.

[2] Exceptions are two North American species endemic to Baja California that only contain zeorin, or appearing deficient in lichen substances, although usnic acid may be present in the cortex (V. corrugata, V. howei).

The thallus structure in some specimens collected more than 100 years ago is not discernible, making it difficult to determine whether or not soredia are present, which is necessary for species identification.

[2] Efflorescence can be slowed or prevented by storing specimens in a frost-free refrigerator below 40 °F, although there may be a trade-off in that long-term storage causes the cortex to become brittle over time (nine yrs).

[2] The same chemical data for Ramalina homalea were also reported by Gerhard Follmann,[7] which again appear to include misidentifications for other lichen substances, without accounting for type specimens.

[5] The "Ceruchis-Group", which was defined by Gerhard Follmann [7] by the presence (−)-16 α-hydroxykaurane, included species subsequently classified by Peter Bowler in three groups within the genus Niebla (1) N. homalea, (2) N. combeoides, and (3) N. ceruchis.

[2][5][7][12] There seems to be no disagreement on the morphological differences between the corticolous and saxicolous groups, only a lack of applying the appropriate types to the names,[2] according to the International Code of Botanical Nomenclature.

[2] The references to the material from which the compound was isolated include a figure showing thalli growing on a cactus, Eulychnia acida, not on sand or rock.