Thallus pale greyish white, thin, corticolous, surface slightly cracked, smooth and dull; apothecia lirelliform, conspicuous, black, numerous, straight or sinuous, sometimes branched, subimmersed to sessile, 1–3(–6) mm long, (0.15–)0.2–0.3 mm wide, lips closed or becoming slightly open, smooth, usually with a well-defined, but sometimes evanescent, thalline margin; proper exciple laterally or almost completely carbonised; hymenium (100–)120–150 µm tall; ascospores 8 per ascus, 2-seriate, fusiform, pale brown, (30–)35–45(–55) µm long, (5–)7–10 µm wide, (7–)8–10(–11)-locular. Chemistry: norstictic acid. Phaeographis australiensis is characterised by the normally closed, black, lirelliform apothecia, the variably carbonised proper exciple and the presence of norstictic acid. When the lips are open the species somewhat resembles the chemically similar Graphis semiaperta Müll. Arg. but that species always has a completely carbonised proper exciple and smaller ascospores. The ascospores in P. australiensis are usually terminally rounded but may sometimes be terminally acute (Hayward 1977: 574, Fig. 7; Fig. 1a). The younger ascospores are often hyaline and older ascospores are conspicuously brown and shrivelled; on occasion, few mature brown ascospores may be seen. Phaeographis australiensis is a common species which occurs in eastern Australia from Queensland to Tasmania and appears to be particularly abundant around Sydney. It occurs on a variety of substrates including species of Avicennia, Banksia, Cassia, Casuarina, Erythrina, Leptospermum, Ligustrum, Hakea, Malus, Melia, Persoonia, Pultenaea and Telopea. It also occurs on Norfolk Island and is reported from New Zealand. Two syntypes of P. australiensis were seen. One of these is labelled ‘LBn 533’, areference to Müller’s publication in Flora, Lichenologische Beitrag no. 533, and is therefore selected as lectotype. The type material of Graphis aulacothecia from WELT consists of 2 syntypes, Knight 7 and Knight 46. Of these, Knight 7 is the larger of the two specimens and is here selected as lectotype as the other smaller specimen has very few apothecia. Graphis aulacothecia was previously reported as a synonym of Phaeographis australiensis (Archer 1999). The morphological variation found in the types of the five names cited above falls within the range of variation seen in the many recent collections. The four later names are based on material collected within a small area near Sydney and it is therefore not surprising that the 11 specimens belong to the same species. Knight reported brown ascospores to be present in Graphis aulacothecia, and also in Graphis elaeina, G. subintricata and G. subtricosa (Knight 1882) but Müller transferred only the last three species to his new genus Phaeographis. Thallus pale reddish-brown, thin, corticolous, surface smooth and slightly shiny; apothecia lirelliform, black, numerous, conspicuous, sessile to slightly immersed, lips closed, becoming slightly open, straight or curved, rarely branched, 1–3 mm long, 0.2–0.3 mm wide, with a thin, evanescent thalline margin; proper exciple laterally carbonised; hymenium 125–150 µm tall; ascospores 8 per ascus, pale brown, ellipsoid, (20–)24–31(–39) × (10–)12–15(–17) µm, 4–6 × 2–3-locular. Phaeographina banksiae is characterised by the black lirellae, the laterally carbonised proper exciple, the small muriform ascospores and the absence of lichen compounds. It is distinguished from other Australian Phaeographina species by the small ascospores. The species is so far known from Queensland, New South Wales and Victoria. Phaeographina echinocarpica is characterised by the large, pale brown ascospores, the conspicuous lirellae and the presence of echinocarpic acid. The carbonised proper exciple is covered with a thin thalline layer thus giving the lirellae a greyish black appearance. Echinocarpic acid is an uncommon benzyl ester distinguished from other esters of this type, such as alectorialic acid and barbatolic acid, by ester formation involving an ortho- rather than a meta-hydroxymethyl group in the B-ring (Elix et al. 1995). Previously echinocarpic acid had been reported only from the Parmeliaceae. The new species is distinguished from other species of Phaeographina with large ascospores, such as P. montagnei (v.d. Bosch) Müll. Arg. and P. muelleri (vide infra), by the presence of echinocarpic acid. The species is so far known only from the two specimens cited. The author is grateful to the Herbaria cited above for the loan of type and other specimens and to the National Herbarium of New South Wales (NSW) for permission to use the facilities of the Herbarium, for arranging the loan of the specimens cited above and to Ms. C. Wardrop (NSW) for the drawings.
Posted on: Tue, 25 Jun 2013 14:58:36 +0000
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