Pertusaria
Type : Pertusaria communis DC., nom. illegit. (Lichen verrucosus Huds.) [=Pertusaria pertusa (L.) Tuck. (=Lichen pertusus L.) – For details of typification see Dibben (1980: 33, 38) and Jørgensen et al. (1994a: 337)].
Descriptions : Flora (1985: 368–369). See also Archer (1997: 34–35).
Key
Key
Pertusaria, together with the genera Ochrolechia A.Massal., Thamnochrolechia Aptroot & Sipman troot & Sipman 1991) and Varicellaria Nyl., is included in the family Pertusariaceae in the order Pertusariales (Eriksson et al. 2004; Pennycook & Galloway 2004), and comprises c. 315 species worldwide (Kirk et al. 2001; Lumbsch & Nash 2002). Subsequent to the Flora account of New Zealand species of Pertusaria (Galloway 1985a), taxonomic studies in the genus in Australasia were begun by Alan Archer, and Gintaras Kantvilas made a study of Tasmanian rainforest species. Both of these workers revised a number of New Zealand taxa and several papers dealing with additional taxa were published (Archer 1990, 1991b, 1991c, 1993, 1995, 1997, 1999a, 2004a; Kantvilas 1990; Archer & Elix 1992, 1993a, 1993b, 1994a, 1994b; Archer & Malcolm 1997; Archer & Messuti 1997), with the result that the genus is now much better known in New Zealand than formerly. Chemistry is of particular value in separating taxa at the species level in Pertusaria and detailed discussions of chemistry in Pertusaria are given in Archer (1995, 1997). The account of North American species of Pertusaria (Dibben 1980) is still an extremely useful monograph with much detailed information. Recent studies on the genus in Thailand (e.g. Jariangprasert et al. 2002, 2004) are disclosing many undescribed taxa there. Seventeen taxa from Tierra del Fuego are discussed by Messuti & Vobis (2003), and eight species are reported from Juan Fernández (Messuti 2005). An annotated key to species occurring in China is given in Zhao et al. (2004).
Pertusaria is characterised by: a crustose thallus; hemiangiocarpous apothecia that are often immersed in thalline verrucae; the presence of a cupulate exciple; primary paraphysoids present in the hamathecium of mature ascomata; thick-walled asci with bivalve dehiscence; and simple, thick-walled, hyaline to brownish ascospores (Lumbsch et al. 1994c; Lumbsch & Schmitt 2001).
Archer (1993: 3–8) utilised chemical and morphological characters to separate and define three subgenera and two sections within Pertusaria. In assigning taxa to subgenera, the species-pair concept of Poelt (1970, 1972) was followed, and it is assumed that sorediate taxa with chlorinated xanthones. e.g. thiophaninic acid, are the sterile counterparts of (hypothetical or actual) fertile, esorediate chemically similar taxa in subgen. Pertusaria. In subgen. Pertusaria the immature ascospores initially present may not all develop and thus asci are found with variable numbers of ascospores; e.g. asci with 8 immature ascospores may give rise to asci with 5–8 mature ascospores, and asci with 4 immature ascospores often develop only 3 mature ascospores, or more rarely, only 1 large spore. The majority of 2-spored asci develop normally. Accordingly, asci with 3 or 4 ascospores are classified as 4-spored, and asci with 5, 6, 7 or 8 ascospores are classified as 8-spored. Ascospores in fertile asci in subgen. Monomurata usually develop normally to give 1, 2, or 8-spored asci, but specimens in this subgenus may often be found lacking ascospores altogether. In New Zealand, species of Pertusaria are accommodated in two subgenera, defined as follows:
There are presently 54 species of Pertusaria known from New Zealand disposed as follows: (1) subgen. Monomurata sect. Monomuratae Archer: P. barbatica, P. circumcincta, P. duppensis, P. erubescens, P. flavovelata, P. jamesii, P. macloviana, P. monticola, P. novaezelandiae, P. psoromica, P. scutellifera, P. sporellula, P. subventosa ssp. subventosa, P. thamnolica, P. truncata and P. velata; (2) subgen Monomurata sect. Digitatae Archer: P. dactylina, P. gymnospora; (3) subgen. Pertusaria : P. albissima, P. alboatra, P. allanii, P. bartlettii, P. celata, P. erumpescens, P. graphica, P. hadrospora, P. hypoxantha, P. knightiana, P. laevis, P. lavata, P. leucodes, P. leucoplaca, P. lophocarpa, P. melaleucoides, P. melanospora, P. micropora, P. muricata, P. murrayi, P. obvelata, P. otagoana, P. paratropa, P. parvula, P. perrimosa, P. petrophyes, P. scottii, P. sorodes, P. spilota, P. subisidiosa, P. subplanaica, P. subverrucosa, P. theochroa, P. thiospoda, P. tyloplaca, P. vallicola and P. xanthoplaca.
Recent molecular work on the phylogeny of Pertusaria and allied taxa (Lumbsch & Schmitt 2001; Schmitt 2002; Lumbsch et al. 2004c) indicates that Pertusaria as presently circumscribed is polyphyletic, comprising three well-supported clades, viz. (1) Pertusaria s. str. – group [comprising Archer's subgen. Pertusaria and subgen. Pionospora]; (2) Monomurata -group; and (3) Varicellaria -group [containing lecanoric acid and septate ascospores](Schmitt 2002). Further molecular work (Lumbsch et al. 2004) confirms the non-monophyly of Pertusaria, with the Pertusariales falling into two groups: (1) a well-supported group, Pertusariales I, including Ochrolechia, Varicellaria and Pertusaria subgen. Monomurata, and (2) a clade that is not well supported, comprising Coccotrema, Melanaria and Pertusaria s. str. An exhaustive analysis to examine phylogeny within the Pertusariales using additional taxa and mitochondrial LSU sequences as an additional genetic marker is under investigation (Lumbsch et al. 2004c: 830).
