Flora of New Zealand Series

Type : Thamnolia vermicularis (Sw.) Ach ex Schaer. [=Lichen vermicularis Sw.]

Description : Flora (1985: 569)

The genus Thamnolia until very recently was considered to be monospecific (T. vermicularis), comprising two subspecies [ ssp. vermicularis, and ssp. solida (M.Satô) W.A.Weber] one of which [ ssp. vermicularis] is widely distributed in alpine localities in all parts of the world (Kärnefelt & Thell 1995). In a recent paper, Santesson (2004) has described two new species in the genus, T. papelillo R.Sant. from the Peruvian Andes and T. juncea R.Sant. from the mountains of Papua New Guinea. Both new species have two different chemical variants (which Santesson recognises as distinct varieties), as in T. vermicularis (see below). It is included in the family Icmadophilaceae (Platt & Spatafora 2000; Stenroos et al. 2002c; Eriksson et al. 2004; Pennycook & Galloway 2004; Eriksson 2005). Apothecia are unknown in the genus and its wide distribution has provoked speculation on possible modes of its dispersal and associated problems of lichen biogeography (Culberson 1963; Sato 1963, 1965a, 1965b, 1968a, 1968b; Sheard 1977; Kärnefelt & Thell 1995; Thomson 1995). Kärnefelt & Thell (1995) discuss morphological variation, ecological behaviour, reproductive biology, lichenicolous fungi, sibling species, species concept, distribution and evolution in Thamnolia and accept two subspecies (vermicularis and solida) of T. vermicularis. They combine the varieties vermicularis (UV−) and subuliformis (UV+) in  ssp. vermicularis, a treatment that is adopted here in preference to earlier accounts accepting two varieties of identical morphology but differing chemistry (Galloway 1985a: 560–570; Malcolm & Galloway 1997: 48). A recent paper on evolutionary relationships in nonsexual lichenised fungi presents molecular data from SSU and LSU rDNA of the genera Siphula and Thamnolia (Platt & Spatafora 2000) that offer unambiguous support for the inclusion of these two genera in the Icmadophilaceae, a view supported by the results of Stenroos et al. (2002c) and now currently accepted (Eriksson et al. 2004; Pennycook & Galloway 2004; Santesson 2004; Eriksson 2005). A recent study of microhabitat requirements of T. vermicularis on Mt Snowdon (Pentecost & Williams 2002) showed that growth occurs mainly in the summer, an observation supported also by grassland lichens, including T. vermicularis, in several habitats in Central Otago (e.g. Lake Onslow, Poolburn Reservoir).

Several lichenicolous fungi occur on Thamnolia vermicularis and in the past these infections were often mistaken for ascomata. The following lichenicolous fungi are known as parasymbionts of Thamnolia : * Cercidospora thamnoliicola Ihlen (Ihlen 1995), * Polycoccum vermicularium (Linds.) D.Hawksw., * Stigmidium frigidum (Sacc.) Alstrup & D.Hawksw., * Thamnogalla cromiei (Mudd.) D. Hawksw.