Characterized by swollen sterile pseudopodetia, areolate, 3–6 cm tall, glossy and usually smooth, chestnut-brown to blackish brown, not perforated, and di- or trichotomously branched. Conidiomata on terminal branches of sterile pseudopodetia, conidia 4–7 µm long, bacilliform. Fertile pseudopodetia robust and taller than sterile pseudopodetia, necrotic at the base, racemosely branched. Apothecia on terminal branches of fertile pseudopodetia, 0.5–1.0 mm wide, disk concave to plane, blackish; ascospores not seen. Secondary chemistry: Fumarprotocetraric acid.

Type: — AUSTRALIA. Tasmania: Lake St. Clair National Park, Trail to Frenchman's cap, 42°12’S 145°59’E, 770 m, Lumbsch 20011c (holotype HO!; isotype F!)

Phylogenetic notes: —Strongly supported as a monophyletic lineage in concatenated multilocus gene tree (ML bootstrap = 100%, posterior probability = 1.0). Cladia tasmanica was previously called clade 9 (Parnmen et al. 2012). This species belongs to an early diverging lineage within the C. aggregata complex sister to all other species in the group.

Reference sequence: — GenBank No. JN115301.

Distribution and habitat: This species is only known from Tasmania, where it grows on soil in wet sclerophyll forests and buttongrass moorland.

Etymology: —Referring to the island of Tasmania where the species is found.

Additional specimens examined (paratypes): — AUSTRALIA. Tasmania: Southwest National Park, March 2009, Lumbsch, Widhelm & Parnmen 19989o, 19994k (F, RAMK).