Giving a brief diagnosis in a footnote, he distinguished it from the similar species P. rudecta and P. borreri by its longer ascospores and conidia, and its more wrinkled amphithecia (the inner layer of the perithecium next to the hymenium).

[2] The original specimens were collected by Alexander Lindig in "Nova Granata" (i.e. [= Republic of New Granada], specifically Bogotá, Colombia), at an altitude of 2,600 m (8,500 ft).

[3] In 1982, Norwegian botanist Hildur Krog transferred the taxon to the newly circumscribed Punctelia, a segregate genus from Parmelia created to contain species with rounded pseudocyphellae.

Specimens reportedly collected from Rio Grande do Sul and from Paraná in 1999 and 2001 were examined later and determined to have been misidentified, representing instead the species Punctelia borrerina.

[3] Major characteristics of Punctelia negata include the presence of small lobes (lobules) on the upper thallus surface, a pale brown lower thallus surface, long threadlike (filiform) conidia, ascospores measuring 19–23 μm long, and a medulla that reacts C− in a lichen spot test.