Flora of New Zealand Series

Type : Cladia aggegata (Sw.) Nyl. [=Lichen aggregatus Sw.]

Description : Flora (1985: 94).

Cladia is a predominantly Southern Hemisphere genus of nine species (Kirk et al. 2001), included in the family Cladoniaceae (Ahti 1993; Wedin et al. 2000a; Stenroos et al. 2002a; Eriksson et al. 2004; Pennycook & Galloway 2004; Eriksson 2005), although Filson (1981, 1992b) included it in a monogeneric family, Cladiaceae, based on the lack of a primary thallus and the presence of an external cartilaginous layer on the pseudopodetia. Current thinking on relationships in the Lecanorales subord. Cladoniineae, de-emphasises the origin of the stipes supporting the hymenial tissue and according to Wedin & Döring (1999: 1132) "The usage of podetial or pseudopodetial structures as circumscribing characters on higher taxonomic levels is thus in considerable doubt, in our opinion, and the homology of these structures in different groups of lichens must be reassessed". The genus is most highly speciose in SE Australia (Filson 1970, 1981, 1992b; Kantvilas & Elix 1987, 1999). In New Zealand species of Cladia are most commonly found in boggy, peaty habitats though some species are widely distributed in both lowland and subalpine grasslands and in forest. Six species are known in New Zealand (Martin 1965; Galloway 1966, 1977a, 1985a, 1992; Malcolm & Galloway 1977b). In a recent study of Cladia in Tasmania, Kantvilas & Elix (1999) recognise eight species and describe five new taxa segregated from the C. aggregata complex, all apparently endemic to Tasmania. In the light of these findings the New Zealand material of C. aggregata, which is both extensive and highly variable, should be re-examined.