Flora of New Zealand Series

Type : Umbilicaria hyperborea (Ach.) Hoffm. [=Lichen hyperboreus Ach., typ. cons.  (see Jørgensen & Santesson 1993: 886)]

Description : Flora (1985: 589).

Umbilicaria, a genus of c. 70 species worldwide (Hestmark 2004), is included in the family Umbilicariaceae (Eriksson et al. 2004; Pennycook & Galloway 2004). It is a conspicuous genus on subalpine to high-alpine rocks, and is a component of the lichen mycobiota of the highest exposed rocks in New Zealand, viz. the rocks of the summit ridge of Aoraki/Mt Cook in land environment (LENZ) T (Leathwick et al. 2003). Around one-third of the known species of Umbilicaria have conspicuous, usually hypothalline, hyphomycetous anamorphs (thalloconidia) in the symbiotic state (Hasenhüttl & Poelt 1978; Hestmark 1990, 1991a, 1991b). Hestmark (1990: 548) defines thalloconidia as "the non-motile, single to aggregated, spherical to irregular, non- to multi-septate, thick-walled, dry, smooth to rugged, dark-coloured conidia developed by the mycobiont and seceded mainly from the lower cortex and/or the rhizinomorphs". Thalloconidia are now recognised as providing good taxonomic characters for species separation (see below). Chemistry in the genus is discussed by Feige et al. (1987), Posner et al. (1992) and Narui et al. (1996, 1999).

Species of Umbilicaria are quite frequently parasitised by the lichenicolous fungus * Clypeococcum grossum (Körb.) D. Hawksworth (q.v.), which has olive-brown, 1-septate ascospores with minutely verrucose walls (Hawksworth 1982; Øvstedal & Hawksworth 1986; Hawksworth & Diederich 1988; Alstrup & Hawksworth 1990; Santesson 1993), and to date, nine species of Umbilicaria in New Zealand are recorded as having infections of this lichenicolous fungus, viz. U. cylindrica, U. durietzii, U. grisea, U. hyperborea, U. nylanderiana, U. polyphylla, U. subaprina, U. umbilicarioides and U. vellea (Galloway 2002c). Material of * Clypeococcum -infected Umbilicaria from New Zealand was earlier incorrectly designated as Lasallia sp. (Galloway 1985a: 203; 1992d: 19), the conspicuous superficial galls being misinterpreted for the pustules that are a common feature of species of Lasallia, a genus not occurring in New Zealand.

Recent studies on Umbilicaria provide much valuable information on various aspects of chemistry, taxonomy, ecology and distribution of species, and the present treatment has benefitted greatly from the secure foundations provided by recent accounts of Northern Hemisphere, Asian, East African, and Antarctic populations of Umbilicaria (Hakulinen 1962; Lindsay 1969; Poelt 1977; Hasenhüttl & Poelt 1978; Seaward et al. 1983; Topham et al. 1982; Krog & Swinscow 1986; Filson 1987; Swinscow & Krog 1988; Codogno et al. 1989; Sancho & Kappen 1989; Hageman & Fahselt 1990, 1992; Hestmark 1990, 1991a, 1991b, 1993, 1997, 2004; Sancho et al. 1992, 1998; Sipman & Topham 1992; Poelt & Nash 1993; Wei & Jiang 1993; Valladares 1994; Goward et al. 1994b; Narui et al. 1996, 1999; McCune & Geiser 1997; Brodo et al. 2001; Øvstedal & Lewis Smith 2001; Romeike et al. 2002). The genus is currently under investigation (Galloway & Sancho 2005, in prep.; Galloway & Ledingham 2006). Seventeen species are recorded here.