Cladoniaceae in 2006. In 2018, Kraichak and colleagues used a technique called temporal banding to reorganize the Lecanoromycetes, proposing a revised system of classification based on correlating taxonomic rank with geological (evolutionary) age. They synonymized the families Squamarinaceae and Stereocaulaceae with the Cladoniaceae, resulting in a large increase in the number of genera and species. The Squamarinaceae had already been included in the Cladoniaceae by previous authors. Although this reorganization has been used in some later publications, the folding of the Stereocaulaceae into the Cladoniaceae was not accepted in a recent analysis. As Robert Lücking explained, "merging of the two families under the name Cladoniaceae is not possible without a conservation proposal because Cladoniaceae (Zenker, 1827) is antedated by Stereocaulaceae (Chevallier, 1826) by one year." Description The thallus of Cladoniaceae lichens are fruticose or foliose, and are often dimorphic–consisting of two distinct forms. The primary thallus is ephemeral to persistent, crustose, foliose or squamulose, while the secondary thallus is typically vertical and holds the ascomata. The secondary thallus ranges in height from a few millimetres to more than . Some species, however, form neither a primary thallus nor any fruticose structures. The ascomata are in the form of an apothecium, and are biatorine, meaning they are of the lecideine type – light in colour and soft in consistency. They often have a reduced margin. Their colour is typically dark brown (sometimes pale brown), red, ochraceous, or black. The hamathecium (referring to all hyphae between the asci in the hymenium) consists of branched paraphyses, and is amyloid. The asci are somewhat fissitunicate, meaning they have two layers that separate during ascus dehiscence. The ascus structure consists of an apical dome and a tube (both of which are amyloid), which is cylindrical to clavate. Ascospores number eight per ascus, and they are usually non-septate, ellipsoid to more or less spherical in shape, hyaline, and non-amyloid. Except for a few genera that produce septate ascospores (Calathaspis, Pycnothelia and Pilophorus), the hymenium does not generally have characters that are useful in taxonomy. The conidiomata are pycnidia; the conidia are non-septate, usually filiform (thread-like), and hyaline. Photobionts The symbiotic algal partner (photobiont) of most Cladoniaceae taxa are unicellular green algae, usually in the genus Asterochloris, but occasionally in the genus Chlorella; both of these genera are in the class Trebouxiophyceae. Eleven species of Asterochloris have found to be associated with genus Cladonia; the algal genus