Although the family has had its classification changed several times throughout its taxonomic history, the use of modern molecular phylogenetic methods has helped to establish its current placement in the order Caliciales.

Some members of this family, particularly those of the type genus, Calicium, are characterized by the presence of thin-walled and short-lasting asci (spore-bearing cells) and a mazaedium, which is an accumulation of loose, maturing spores covering the surface of the fruiting body.

Although the family is best represented in mountainous areas of temperate and tropical regions, a few hardy species can survive the harsh environment offered by Antarctica's McMurdo Dry Valleys by growing in cracks on the surface of rocks.

[5] Historically, the family has also been placed by various authors in the orders Coryneliales, Helotiales, and the now-obsolete Sphaeriales, depending on which phenotypic characteristics were considered to be the most important.

[6] The Swedish lichenologist Leif Tibell spent much of his career studying calicioid lichens, and used a variety of techniques to help him understand relationships of taxa in this group,[7] including phenetic and cladistic analyses of morphology, and investigation of secondary chemistry.

He suggested in 1984 that the order was polyphyletic (i.e., it did not originate from a single common ancestor) and that the main identifying features of the Caliciales had evolved independently in several different unrelated groups.

[8][9] Preliminary phylogenetic analysis showed that Mycocaliciaceae and Sphinctrinaceae belonged to the class Eurotiomycetes, while Caliciaceae appeared to group with the order Lecanorales.

[5][10][4] The six genera that were included by Tibell in the Caliciaceae in his 1984 proposed classification of calicioid fungi (Acroscyphus, Calicium, Cyphelium, Texosporium, Thelomma, and Tholurna)[8] are still in the family today.

[17] A large molecular study of the Caliciaceae-Physciaceae clade published in 2016 has helped to sort out natural relationships in this group, and more clearly define generic delimitations.

These three genera are distinguished from other Caliciaceae in the appressed foliose growth form (like small leaves pressed flat against the substrate), the absence of a mazaedium, and ecologically by their predominance in the subtropics and tropics.

[1] The genus Acroscyphus, which contains the single widespread but rare species A. sphaerophoroides, is a peculiar exception to the typical morphology of the Caliciaceae: it has a finger-like (dactyliform) thallus, immersed ascocarps on podetia (hollow stalks), and a yellow to orange medulla.

[19] The spores of Texosporium lichens have a unique ornamentation that is created by paraphyses that stick to the surface; this feature may help provide protection against desiccation or DNA-damaging radiation encountered when exposed in sunny habitats.

[1] Acroscyphus is again an exception, as it contains secondary compounds not found in other Caliciaceae, including chloroatranorin, rugulosin, zeorin, and chrysophanic acid.

[60] That proposal had attempted to retain B. disciformis as the type for Hafellia, so that the name could continue to be used for a distinctive group of crustose lichens with thickened ascospore walls that had historically been treated in Buellia.

Examples include: the side of a tree not inhabited by other corticolous species, in the cracks of deep fissures in bark, or woodpecker holes.

[63] Similar results were reported in studies on mangrove forests in India,[64] and the Gulf of Thailand,[65] where the genera Dirinaria and Pyxine were found to be amongst the most common foliose lichens.

This region features one of the most harsh environments on earth, with wide variations in temperature, extreme aridity, limited nutrients, and high levels of solar and UV radiation.

[76] Studies conducted in India suggest that Pyxine cocoes, a common, pollution-tolerant foliose lichen, is a candidate for biomonitoring of local air pollution.

This extremophile lichen has been exposed to conditions simulating those encountered in space and on celestial bodies like Mars, including vacuum, UV radiation, and extreme dryness.

B. frigida has demonstrated resilience to these space-related stressors, making it a candidate for studying how life can adapt to and potentially survive in extraterrestrial environments.

[83] A Baltic amber fungus fossil, originally collected by Robert Caspary and assigned to the genus Stilbum (family Chionosphaeraceae) in 1886, was reassessed as a member of the Caliciales in 2019, as Calicium succini.