LICHENICOLOUS SPECIES OFARTHONIAONLOBARIACEAEWITH NOTES ON EXCLUDED TAXA

Lichenologist 30(1): 59–91 (1998)

LICHENICOLOUS SPECIES OF ARTHONIA ON LOBARIACEAE WITH NOTES ON EXCLUDED TAXA Mats WEDIN* and Josef HAFELLNER‡

Abstract: The species of Arthonia s. lat. (Arthoniales, Ascomycotina) lichenicolous on species of Pseudocyphellaria and other Lobariaceae are revised. Thirteen species are accepted, and eight species are described as new (all from the Southern Hemisphere): Arthonia badia Wedin & Hafellner, A. coriifoliae Wedin & Hafellner, A. flavicantis Wedin & Hafellner, A. maculiformis Wedin & Hafellner, A. minuta Wedin & Hafellner, A. santessoniana Wedin & Hafellner, ‘A.’ semi-immersa Wedin & Hafellner, and A. subaggregata Wedin & Hafellner. Comparative notes on additional accepted species previously described from Pseudocyphellaria or other Lobariaceae (A. pelvetii, A. plectocarpoides, A. pseudocyphellariae, A. stictaria, and A. subconveniens) are included, and a key to the Arthonia (and similar) species growing on Lobariaceae is presented. The coelomycete genus Subhysteropycnis Wedin & Hafellner is described for the species S. maculiformans Wedin & Hafellner, the macroconidal anamorph of Arthonia badia. The lecanoralean genus Corticiruptor Wedin & Hafellner is described as new to accommodate the single lichenicolous species C. abeloneae (P. M. Jørg.) Wedin & Hafellner comb. nov., and the additional new combination Plectocarpon linitae (R. Sant.) Wedin & Hafellner is proposed. The names Celidium pelvetii Hepp, Sticta aurata b abortiva Schaer. and Arthonia stictaria Nyl. are lectotypified, and the typifications are discussed. ? 1998 The British Lichen Society

Introduction Arthonia Ach. is one of the largest genera of lichenized and lichenicolous ascomycetes, comprising more than 500 species (Grube et al. 1995), according to the current, wide generic concept. During fieldwork in the Southern Hemisphere, several conspicuous Arthonia species have been collected on species of Pseudocyphellaria. Some host genera are well known to have a particularly rich Arthonia-flora and other lichenicolous fungi. Pseudocyphellaria hosts a particularly large number of lichenicolous fungi: Kondratyuk & Galloway (1995) refer to 51 species in 23 genera. Several genera, such as Peltigera, Lecanora and Pseudocyphellaria, are also known to possess species with more than one Arthonia species associated. The main aim of the present study was to revise the species of Arthonia s. lat. growing on hosts of the family Lobariaceae (incl. Stictaceae), to provide full descriptions of the new species found, and to compare them with, and briefly characterize, other Arthonia species already described from members of the Lobariaceae. Arthonia is in great need of a critical re-assessment of the generic *Botany Department, The Natural History Museum, Cromwell Road, London SW7 5BD, UK. ‡Institut für Botanik, Karl-Franzens-Universität, Holteigasse 6, A-8010 Graz, Austria. 0024–2829/98/010059+33 $25.00/0 li970116

? 1998 The British Lichen Society

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circumscription, and some of the species treated below are probably not closely related to the core group of Arthonia, including its type species (the A. radiata group). We have treated Arthonia in a very broad sense, including several more or less distinct subgroups, and a few species that differ in many important respects and clearly do not belong to Arthonia in a more restricted sense. This has been commented upon when relevant, and in the cases of Arthonia abeloneae P. M. Jørg. and Arthonia linitae R. Sant., we feel that it is justified to formally exclude them from Arthonia and introduce the new genus Corticiruptor Wedin & Hafellner, and the new combination Plectocarpon linitae (R. Sant.) Wedin & Hafellner, respectively, for these species. The first Arthonia to be described from a Pseudocyphellaria was Sticta aurata b abortiva Schaer. (Schaerer 1850), a taxonomic synonym of Celidium pelvetii Hepp (Hepp 1857), [Arthonia pelvetii (Hepp) H. Olivier (Olivier 1906)]. This fungus was originally described from France. Arthonia stictaria Nyl. and A. subconveniens Nyl. (Nylander 1867) were later described from New Zealand and Brazil, respectively, and A. ricasoliae Müll. Arg. (Müller 1887) was later added from Australia. Kondratyuk & Galloway (1994, 1995) reported several Arthonia species from a number of Pseudocyphellaria species, without, however, citing any specimens in the latter publication. Some of the determinations seem doubtful and may refer to species here described as new, or to additional, still undescribed species. Arthonia epiphyscia, reported by Kondratyuk & Galloway from P. multifida, is a common commensalistic fungus on species of Physcia, and A. fuscopurpurea, reported from P. dissimilis, is a distinctive species on Peltigera. Arthonia epiphyscia is briefly compared with A. minuta, and A. fuscopurpurea is briefly mentioned under A. subconveniens. The specimens of A. pelvetii reported by them from P. poculifera belongs to A. stictaria, but the specimen on P. rufovirescens has not been re-studied by us. We have not been able to search for and re-study all the collections from Kondratyuk & Galloway (1995), but where occasionally we have come across specimens annotated by Kondratyuk in BM, we have included them and commented upon them below. Material and Methods The study is based mainly on the first author’s collections from fieldwork in Chile and Argentina conducted during 1989, and to a lesser extent on additional collections from New Zealand (fieldwork undertaken 1990, 1992, 1995) and Australia (1990, 1992). Selected herbarium material from BM, E, G, GZU, H-NYL, UPS and the private herbaria of J. Hafellner (hb. Haf.) and P. Diederich (hb. Died.) have also been investigated. Anatomical observations and measurements were undertaken on thin sections mounted in water or Lugol’s solution (Merck 9261); photo-documentation (bright-field or interference contrast) was usually conducted on sections mounted in water or lactic blue (lactophenol with cotton blue) or, for the study of conidiogenesis, erythrosin in ammonia; hymenial reactions were recorded using Lugol’s solution before and after treatment with a 10% KOH solution. Measurements and observations of anatomical details were made at a magnification of 1000 times, using oil immersion optics. For ascospores and conidia, at least ten measurements per specimen were taken. All material cited (including types) has been studied, unless otherwise noted. Herbarium abbreviations follow Holmgren et al. (1990), with the addition of Centro Universitario Regional Bariloche, Argentina (BCRU).

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Morphology and anatomy Ascomata The ascomatal shape varies to a considerable extent in Arthonia, and we have identified two main types of apothecia in the genus. Several species form sessile to somewhat stalked apothecia (‘ lecideoid ’), as in A. minuta (see Fig. 5B) and A. subaggregata. Others form superficial, fleck-like maculae, as in A. badia, A. flavicantis (see Fig. 4A), A. pelvetii and A. subconveniens, which sometimes may be distinctly raised, as in A. coriifoliae (see Fig. 4C). This latter reaction approaches a gall formation, something which is clearly present in A. plectocarpoides (see Fig. 7A). Arthonia santessoniana produces apothecia that are somewhat intermediate between the lecideoid and fleck-like types. ‘ Arthonia ’ semi-immersa (see Fig. 8C), which does not belong to Arthonia in a more restricted sense, and the lecanoralean fungus Corticiruptor abeloneae (see Fig. 10C–E), have apothecia that are&immersed in the host tissue, at least in the early stages of development. Hymenial reactions The hymenium and hypothecium react I+ red or blue, and K/I+ blue, in all species except ‘ A. ’ semi-immersa, which is completely I negative. A group of species including A. badia, A. coriifoliae, A. flavicantis, and A. plectocarpoides, all have an I+ pale blue reaction with Lugol’s solution before treatment by KOH. The other species all react I+ reddish before treatment by KOH. Asci Most of the species treated have either a broadly clavate ascus or a pyriform to subglobose ascus. Arthonia minuta, A. santessoniana and A. subaggregata have a small, K/I+ apical ring-structure (Fig. 1A); most other species have I" asci. Corticiruptor abeloneae deviates considerably from the other species in having asci with an amyloid tholus; this fungus belongs to Lecanorales. The asci are similar to the Micarea-type (Hafellner 1984), i.e. having a paler central part surrounded by a more strongly amyloid tube. Plectocarpon linitae has asci of the Opegrapha-type (Bellemère & Letrouit-Galinou 1987: plate 3 fig. A). Ascospores Almost all of the species treated here have one-septate ascospores, with the exception of Plectocarpon linitae (three-septate), and Corticiruptor abeloneae (non-septate). The spore shape varies considerably between species, and may be oblong, ovoid, ellipsoid or soleiform. Several species have ascospores with a&distinct perispore, which, later in their development, forms a brown, granular spore surface. The perispore apparently, at least in some species, reacts I+ red, which, together with the iodine colour itself, often gives the ascal contents a red colour after treatment with Lugol’s solution. Hamathecium The hamathecium is composed of filaments that vary considerably between species, and several&distinct types are recognized. In the species groups

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F. 1. Asci and paraphysoids, in Lugol’s solution. A, Arthonia minuta (Wedin 1192b); ascus with amyloid ring-structure; B, A. flavicantis (holotype); C, A. badia (Santesson 732); D, A. subaggregata (Wedin 1253c); branched, pigmented paraphysoids; E, ‘ A. ’ semi-immersa (holotype); narrowly clavate asci and sparingly branched, erect hamathecial filaments; F, A. badia (Santesson 732); paraphysoids with pigmented upper parts and apical caps; G, A. coriifoliae (Wedin 1087); paraphysoids with apical caps. Scale=10 ìm.

with sessile ascomata (A. minuta, A. santessoniana, A. subaggregata), and in A. maculiformis, A. stictaria and A. subconveniens, the paraphysoids are&richly branched in the epithecium and extend laterally above the asci (Fig. 1D). The

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branched paraphysoids in these species have no apical caps, but may be&embedded in a pigmented gel. In A. maculiformis, the pigmentation of the epithecium is very strong and may cause problems when interpreting the structure. In the group with fleck-like apothecia and an I+ pale bluish hymenium (A. badia, A. coriifoliae, A. flavicantis, and A. plectocarpoides) the paraphysoids are erect, thickened at the apices and with distinct apical caps in the epithecium (Fig. 1F–G). Arthonia pelvetii has&erect, little pigmented and unbranched apical parts of the paraphysoids (see Fig. 5C); the same is true for A. pseudocyphellariae. ‘ Arthonia ’ semi-immersa has stout, erect hamathecial filaments, which are very little branched (Fig. 1E). Corticiruptor abeloneae has simple, sparingly branched hamathecial filaments that are not or only slightly thickened in the tips (see Figs 10C & 11). Plectocarpon linitae has distinct, comparatively thin, richly branched and anastomosing hamathecial filaments, typical of the family Opegraphaceae (see Fig. 10A). The brown pigment in all species with pigmented epihymenia become greenish black in K, with the exception of A. pelvetii, where the epihymenium only becomes pale greenish (most likely due to the very low concentration of the pigment), and ‘ A. ’ semi-immersa, where the epihymenium becomes slightly more pale brownish (due to a different pigment present). Pycnidia and conidia Pycnidial anamorphs are sometimes found together with Arthonia ascomata, and below we describe the new anamorph genus Subhysteropycnis for a common, characteristic and conspicuous coelomycete, apparently being the macroconidial anamorph of the new species A. badia (see Fig. 3B–D). Several types of Arthonia anamorphs are known. Vobis (1980) describes pycnidia of the ‘ Lecanactis-type ’ with conidiophores of ‘ type I ’ (in A. phaeobaea approaching type II) and small, oblong to ovate microconidia from A. phaeobaea (Norman) Norman and A. medusula (Pers.) Nyl., and pycnidia with carbonized walls, producing long, filiform conidia in A. galactites (DC.) Dufour. Matzer (in Grube et al. 1995) described the anamorph genus Helicobolomyces (based on H. lichenicola) for the anamorph of A. cinnabarinula Müll. Arg. This species has remarkable, coil-shaped, multicellular brownish macroconidia. Grube et al. (1995) also reported bacilliform microconidia to be present in A. cohabitans Coppins. Matzer (1996) reports rod-shaped microconidia from the lichenicolous species A. pseudographina Matzer and A. santessonii Matzer, and in addition, irregular, often branched, multicellular macroconidia occur in A. intermedia Matzer, A. pseudographina and A. santessonii. Coppins (1989) mentions hyaline, aseptate and rod-shaped (bacilliform or oblong) microconidia from several British lichenized and lichenicolous species: A. anombrophila Coppins & P. James, A. graphidicola Coppins, A. ilicina Taylor, A. ilicinella Nyl., and A. invadens Coppins. Coppins (1992) reported on the pycnidia and conidia of a number of British Arthonia species in addition to those mentioned above. He noted the presence of two main types of conidia; rod-shaped or bacilliform [found in A. cinnabarina (DC.) Wallr., A. didyma Körb., A. fuscopurpurea (Tul.) R. Sant., A. gelidae R. Sant.,

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A. intexta Almq., A. lapidicola (Taylor) Branth & Rostr., A. muscigena Th.Fr. (as A. leucodontis (Poelt & Döbbeler) Coppins), A. myriocarpella Nyl., A. radiata (Pers.) Ach., A. stellaris Krempelh., A. vinosa Leight.]. Sometimes the bacilliform conidia may become narrowly ellipsoid as in A. spadicea Leight., and thread-like conidia are found in A. endlicheri (Garov.) Oxner and A. impolita (Hoffm.) Borrer. We have also noted hyaline, simple, bacilliform microconidia to be produced by some of the species reported on here: in A. badia, A. subaggregata (see Fig. 7D) and probably also in A. flavicantis, and in Plectocarpon linitae (see Fig. 10B). Key to species of Arthonia and similar fungi growing on Lobariaceae 1.

Ascomata orange-red, K+ strong violet . . . . . . . . . . . . . . . 8. A. pseudocyphellariae Ascomata brownish or black, not K+ violet . . . . . . . . . . . . 2

2.

Ascomata&immersed in host tissue; spores hyaline . . . . . . . 3 Ascomata superficial from an early stage; spores hyaline or becoming brownish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3 (2)

Ascal wall and gel I+ blue; ascospores simple, c. 11–13#3–5 ìm . 15. Corticiruptor abeloneae Ascal wall and gel I"; ascospores 1-septate, c. 14·5–18#5–7 ìm . 10. ‘A.’ semi-immersa

4 (2)

Ascospores becoming brown; ascomata fleck-like, forming&round maculae on the host thallus; epithecium strongly dark pigmented or with dark apical caps . . . . . . . . . . . . . . . . . . . . . 5 Ascospores hyaline; ascomata fleck-like or lecideoid; epithecium& pigmented or not . . . . . . . . . . . . . . . . . . . . . . . . . 9

5 (4)

Infection obviously parasitic; hymenium in section I+ red; paraphysoids strongly pigmented, branched and extending laterally in the epithecium, but without apical caps . . 4. A. maculiformis Infection not or only very weakly parasitic; hymenium in section I+ pale bluish (without pre-treatment of KOH); paraphysoids in epithecium erect and with distinct apical caps . . . . . . . . . 6

6 (5)

Ascomata covering hemispherical galls . . . 7. A. plectocarpoides Ascomata not distinctly gall-inducing, but sometimes&raised . . 7

7 (6)

Ascomata with a dull, chestnut brown colour, somewhat convex . . 1. A. badia Ascomata black, often distinctly raised when older . . . . . . . . 8

8 (7)

Ascomata glossy; spores soleiform . . . . . . . . 3. A. flavicantis Ascomata dull; spores oblong–ovoid . . . . . . . 2. A. coriifoliae

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9 (4)

Ascomata fleck-like, forming&round maculae on the host thallus (see also species no. 9) . . . . . . . . . . . . . . . . . . . . . 10 Ascomata lecideoid, superficial . . . . . . . . . . . . . . . . . . 14

10 (9)

Ascospores 3-septate; ascomata multilocular . . . . . . . . . . . 11 Ascospores 1-septate; ascomata unilocular . . . . . . . . . . . . 12

11 (10) Ascomata pale brown . . . . . . . . . . 14. Plectocarpon linitae Ascomata black . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. macaronesiae (not treated here; Diederich & Etayo 1994) 12 (10) Ascomata brownish; ascospores oblong–ovoid, c. 11–13·5#4·5– 5·5 ìm; on Pseudocyphellaria . . . . . . . . . . . . . . . . . . 13 Ascomata black or dark brown; ascospores narrowly oblong to soleiform, c. 13–15#4 ìm; on Lobaria . . . . . . . . . . . . . . 13. A. subconveniens 13 (12) Paraphysoids erect; epithecium indistinct and&unpigmented . . . 6. A. pelvetii Paraphysoids&extending laterally above the asci; epithecium distinct, &pigmented . . . . . . . . . . . . . . . . 11. A. stictaria 14 (9)

Ascomata&aggregated; ascospores c. 8–10·5#3·5–4·5 ìm . . . . . 12. A. subaggregata Ascomata scattered; ascospores c. 9·5–14#4·5–6 ìm . . . . . . 15

15 (14) Ascomata brownish, ¡c. 0·1 mm diam.; ascospores c. 9·5–12 (–14)#4–5·5 ìm . . . . . . . . . . . . . . . . . . 5. A. minuta Ascomata black, up to c. 0·3 mm diam.; ascospores c. 11–14#4·5– 6 ìm . . . . . . . . . . . . . . . . . . . . . 9. A. santessoniana The Species 1. Arthonia badia Wedin & Hafellner sp. nov. Species differt ab Arthonia flavicantis ascomatibus nigrofuscis et forma ascosporarum et ab Arthonia coriifoliae ascomatibus nigrofuscis parce elevatis et ascosporis praecox fuscescentibus. Typus: Chile, Region XII: Torres del Paine Nat. Park, c. 15 km WNW of the Park Administration, Rio Pingo, along Chorillo los Salmones, on Pseudocyphellaria granulata, 51)07*S, 73)11*W, 60–90 m, 1989, Wedin 1160 (UPS—holotypus; BM, BRCU, GZU–isotypi). Exsiccata: Lechler, Pl. Magellan. nos 984 and 985. [sub Sticta granulata].

(Figs 1C, ascus; F, paraphysoids; 2A, ascospores; 3A, hymenium) Description: More or less rounded on the thallus of Pseudocyphellaria granulata. Apothecia&rounded, dark chestnut brown to almost black, superficial, fleck-like, somewhat convex but usually not very raised, c. 0·4–1·0 mm diam., c. 40–55 ìm tall in section (Fig. 3A). Epithecium c. 5–15 ìm tall, dark brown; becoming greenish black in K. Hymenium c. 25–35 ìm tall, hyaline, I+ pale bluish, K/I+ blue. Hypothecium c. 10–15 ìm tall, hyaline, I+ pale bluish.

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F. 2. Ascospores. A, Arthonia badia (Santesson 732); B, Arthonia coriifoliae (Wedin 1087); C, A. flavicantis (holotype); D, A. maculiformis (Wedin 2492); E, A. minuta (Wedin 1192b), Scale=10 ìm.

F. 3. Arthonia badia A, longitudinal section of hymenium, in lactic blue (Santesson 732); B–D, Subhysteropycnis maculiformans B, longitudinal section of group of pycnidia, in water/interference contrast; C, pycnidium with conidiogenous cells and macroconidia, in lactic blue/interference contrast; D, conidiogenous cells and macroconidia, in erythrosin/interference contrast (Wedin 1095). Scale=25 ìm.

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Paraphysoids (Fig. 1F) indistinct in lower parts, c. 1·5–2·5 ìm in the hymenium; in the epithecium distinctly thickened, c. 3–5(–6) ìm wide, with a granular brown pigment and distinct brown apical caps. Asci (Fig. 1C) broadly clavate, c. 25–33#15–22 ìm; no amyloid ring observed in K/I; 8-spored. Ascospores (Fig. 2A) c. 12–14(–15)#5–6(–7) ìm, 1-septate, distinctly constricted at septum, oblong–ovoid to ellipsoid, upper cell density usually wider than the lower, hyaline with a distinct perispore (c. 0·5–1 ìm thick in water) at first, rapidly becoming brown and verrucose. Pycnidia producing microconidia immersed in or in close connection with the hymenia were observed in a few sections, c. 65–85 ìm wide; wall pale brown, c. 10–14 ìm thick, apically dark brown. Microconidia c. 4–6#1·5 ìm, rod-shaped. Macroconidia produced by the synanamorph Subhysteropycnis maculiformans. Notes: Arthonia badia is, in several anatomical characteristics, similar to A. flavicantis; hymenial gel with an I+ pale bluish reaction, completely non-amyloid asci in K/I, and spores that rapidly become brown and verrucose. The two species are most easily separated on their different gross morphology, A. flavicantis having smaller, distinctly black apothecia and A. badia having larger, dull dark brown apothecia, and by the shape of the spores. Arthonia badia may resemble A. coriifoliae, which also has the I+ blue hymenial reaction, but the latter species differs in having more distinctly raised, black apothecia, and in having spores that remain hyaline for a longer time. Arthonia plectocarpoides differs in forming distinct galls and in usually having darker, &black apothecia. Arthonia badia is probably weakly parasitic as the infection usually only causes a narrow zone of discoloured host tissue around the Arthonia ascomata, if any damage is visible at all. In some collections, the central parts of the host are, however, darker in colour, which in some cases could be interpreted as damage caused by the Arthonia. This discolouration may, however, be due to normal ageing of the host thallus, which also might be influenced by the action of multiple infections of several lichenicolous fungi. Pseudocyphellaria granulata hosts numerous lichenicolous fungi, of which hitherto only Abrothallus granulatae and the corresponding anamorph Vouauxiomyces granulatae have been described (Wedin 1994). These species also occur admixed with Arthonia badia in the exsiccatum Lechler, Pl. Magellan. no. 985. In the paper by Wedin (1994: 306), A. badia (as an unidentified Arthonia) was mentioned briefly under Abrothallus granulatae. Arthonia badia is restricted to southernmost South America, and the fungus has not been found on material of the host from other areas, despite careful searches of herbarium material. Additional material investigated: Argentina: Tierra del Fuego: Sierra Alvear, the southern slope, above Las Cotorras (about 20 km ENE of Ushuaia), 1940, Santesson 732 (UPS).—Chile: Region XII: Punta Arenas, Lechler, Pl. Magellan. no. 984 (UPS); as above, no. 985 (BM, UPS); Isla Navarino, 15 km S of Puerto Williams, in valley SE Diente de Navarino, 56)03*S, 67)35*W, 1989, Wedin 1233b (UPS); as above, 2·5 km S of Puerto Williams, in valley of Rio Ukika, along the track to Diente de Navarino, 55)57*S, 67)36*W, 1989, Wedin 1249d (UPS).

The ascomata of A. badia are always associated with a peculiar coelomycete, which produces macroconidia. Wedin (1994: 306–307) mentioned this

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fungus in the descriptions of Abrothallus granulatae and Vouauxiomyces granulatae, and gave a very brief description of it. The generic name Subhysteropycnis is here suggested to accommodate this very characteristic anamorph, as it often occurs without the teleomorph. Subhysteropycnis Wedin & Hafellner gen. nov. Pycnidia frequenter aggregata in maculis decoloribus, erumpentia, demum sessilia, applanata, rotundata ad aliquot elongata, ostiolis elongatis instructa. Paries basaliter hyalinus apicaliter fuscus cellulis subglobosis compositus. Conidiophora desunt. Cellulae conidiogenae partibus basalibus et lateralibus parietis exorientes, hyalinae, lageniformes ad cylindricae, monoblasticae, sine zonis proliferantibus. Conidiogenesis terminalis, indistincte phialidica. Macroconidia singularia, unicellularia, non aggregata in gelatina, bacilliformia, basaliter truncata. Typus: Subhysteropycnis maculiformans Wedin & Hafellner.

Etymology: From sub-(Latin)=somewhat, almost, hysterinus (Latin)= elongated with a cleft-life opening, like the ascoma of Hysterium, and pycnos (Greek)=dense, compact. The name refers to the somewhat elongated ostioles of the pycnidia. Description: Conidiomata pycnidial, erumpent, &sessile, flattened, round to&elongated, with a distinct, &slit-like ostiole, scattered to normally densely aggregated and arising within&discoloured, pale brownish spots, predominantly on the upper side of host thallus; upper conidiomatal wall composed of dark brown, &rectangular to irregular cells, becoming greenish black in K; lower conidiomatal wall hyaline. Mycelium immersed in the host tissue, particularly in the uppermost part of the cortex; thick-walled hyphae easily observed in connection with, and growing from, the pycnidia in infected areas, hyphae I+ orange. Conidiophores absent. Conidiogenous cells lining the pycnidial cavity basally and laterally, hyaline, monoblastic, lageniform to cylindrical, sometimes&ulliform, producing conidia terminally; conidiogenesis enteroblastic, collarettes rather indistinct. Macroconidia simple, hyaline, smooth-walled by light microscopy, bacilliform; apex rounded; base distinctly truncated. Subhysteropycnis maculiformans Wedin & Hafellner, spec. nov. Species in thallo Pseudocyphellariae granulatae parasitans. Pycnidia aggregata, 0·03–0·1 mm in diam., strato externo corticis superioris erumpentia. Cellulae conidiogenae 4·5–12#2·5–3·5 ìm. Conidia bacilliformia, basim versus aliquot attenuata, 6·5–10·5#1·5–3 ìm. Typus: Chile, Region XII: Isla Navarino, 2·5 km S of Puerto Williams, in valley of Rio Ukika, along the track to Diente de Navarino, 55)57*S, 67)36*W, 1989, Wedin 1249c (UPS—holotypus; BM, GZU—isotypi). Exsiccata: Lechler, Pl. Magellan, nos 984 and 985 [sub Sticta granulata].

(Fig. 3B–D) Description: More or less parasitic on the thallus of Pseudocyphellaria granulata, forming c. 0·2–1·2 mm wide, roundish&brownish spots, that sometimes become confluent in larger patches. Pycnidia (Fig. 3B– C)&densely aggregated in the spots, occasionally scattered, c. 0·03–0·1 mm

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wide; upper pycnidial wall c. 12–25(–35) ìm thick, composed of c. 4–10 hyphal layers, lower wall hyaline, c. 3–4 cells thick. Pycnidial gel I& pale blue; K/I+ blue. Conidiogenous cells (Fig. 3D) c. 4·5–12#2·5–3·5 ìm. Conidia (Fig. 3D) bacilliform, c. 6·5–10·5#1·5–3 ìm. Notes: Subhysteropycnis maculiformans is a very characteristic fungus, which seems to form the stage before the teleomorph is developed. It is often found without the teleomorph, which justifies the formal naming, and may be abundant on the host. Subhysteropycnis maculiformans is recognized in the field by the dense clusters of characteristically somewhat flattened pycnidia, which are produced in&pale brownish spots on the host; these spots occasionally becoming confluent to form larger patches. The brownish spots may eventually be filled up by the ascomata of the teleomorph. The ostiole is usually somewhat elongated, a characteristic feature recalled in the generic name. Subhysteropycnis maculiformans was first noted by Rolf Santesson, who also gave it a herbarium name. The apothecia of Arthonia badia apparently develop within the infection spots housing the Subhysteropycnis pycnidia, eventually replacing the latter, and it is possible to follow the development from Subhysteropycnis to Arthonia in several of the collections investigated. The pycnidial gel of Subhysteropycnis reacts faintly I+ blue in low concentrations of Lugol’s solution, and clearly K/I+ blue; this is exactly the same kind of reaction as in the hymenium of the teleomorph. In sections, the tissue below the pycnidia sometimes reacts I+ faint blue, and this is interpreted as a developing Arthonia hymenium. Arthonia badia has always been found in immediate connection with S. maculiformans. These circumstances are taken as convincing evidence for the anamorph– teleomorph connection. In addition to the macroconidial-producing Subhysteropycnis-anamorph, A. badia produces normal, rod-shaped microconidia similar to most other microconidia reported from Arthonia species (see above). Additional material investigated (also present in the collections cited under Arthonia badia): Argentina: Tierra del Fuego: Tierra del Fuego Nat. Park, c. 9·5 km W Ushuaia, at the Cascada Rio Pipo, 54)48*S, 68)30*W, 1989, Wedin 1095 (UPS); as above, N of Cascada Rio Pipo, 54)45*S, 68)30*W, 1989, Wedin 1105 (UPS); Glacial Martial, below the lower chain lift station, along the stream, 54)47*S, 68)23*W, 1989, Wedin 1116 (UPS); Monte Martial, the southeastern slope, above Ushuaia, 1940, Santesson 458 (UPS).—Chile: Region XII: Torres del Paine Nat. Park., c. 15 km WNW of the Park Administration, Rio Pingo, along Chorillo los Salmones, 51)07*S, 73)11*W, 1989, Wedin 1144 (UPS); Isla Navarino, 6·5 km S Puerto Williams, in valley SE Diente de Navarino, 55)59*S, 67)35*W, 1989, Wedin 1219 (UPS); as above, 15 km S of Puerto Williams, 56)03*S, 67)35*W, 1989, Wedin 1223a (UPS, IMI, M); Tierra del Fuego: Rio Condor, 1896, Dusén (UPS).

2. Arthonia coriifoliae Wedin & Hafellner sp. nov. Species differt ab Arthonia badia ascomatibus nigris maioribus elevatis, ab Arthonia flavicantis ascomatibus impolitis et forma ascosporarum, et ab Arthonia plectocarpoides defectu cecidiis et ascosporis minoribus. Typus: Chile, Region XII: Isla Navarino, 6·5 km S Puerto Williams, in valley NE of Diente de Navarino, 55)59*S, 67)35*W, 1989, Wedin 1216a (UPS—holotypus; BM, GZU—isotypi).

(Figs 1G, paraphysoids; 2B, ascospores; 4C–D, hymenium)

F. 4. A–B, Arthonia flavicantis (holotype); A, longitudinal section of hymenium, in lactic blue/interference contrast; B, paraphysoids and asci, lactic blue/interference contrast; C–D, A. coriifoliae (Wedin 1087); C, longitudinal section of hymenium, note the raised portion of host tissue under the ascoma, lactic blue/interference contrast; D, paraphysoids and asci, lactic blue. Scale=25 ìm.

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Description: Weakly parasitic on Pseudocyphellaria coriifolia. Apothecia scattered, very dark brown to almost black, matt, fleck-like, superficial, distinctly rounded but sometimes somewhat confluent, rarely surrounded by a slightly discoloured narrow zone, usually convex and distinctly raised (Fig. 4C), c. 0·5–1·1 mm diam., in section c. 45–55 ìm tall. Epithecium c. 8–15 ìm tall, dark brown, changing to greenish black in K. Hymenium c. 25–35 ìm tall, hyaline, I+ very pale blue in low conc., K/I+ blue. Hypothecium c. 5–12 ìm tall, pale brownish, K". Paraphysoids (Figs 1G, 4D) c. 1·5–2(–3) ìm in the hymenium, hyaline; in the epithecium erect, apices thickened and with distinct dark brown caps, c. 3–6(–7) ìm wide, caps becoming greenish black in K. Asci (Fig. 4D) broadly clavate, c. 25–35#17– 20 ìm; no ring-structure visible in K/I, 8-spored. Ascospores (Fig. 2B) c. 11–12(–14)#5–6(–7) ìm, 1-septate, constricted at septum, oblong– ovoid, hyaline and smooth with a distinct perispore (c. 0·5–1 ìm thick in water) but later becoming brown and warted; perispore I+ red. Pycnidia not seen. Notes: The pale bluish iodine reaction in the hymenium of A. coriifoliae and similar species is most easily seen in somewhat squashed hand sections, particularly in low concentrations of Lugol’s solution. The perispore reacts I+ red and may, together with the iodine colour itself, obscure the blue colour in higher concentrations of the iodine solution. Arthonia coriifoliae seems to be a very weak parasite. It is easily recognized by the large, often distinctly raised apothecia, and differs from the similar species A. badia by the shape and colour, and from A. flavicantis by the size and dull colour of the apothecia, and by the shape of the spores. Arthonia plectocarpoides differs by the more distinctly gall-forming infections, and by having larger spores and asci, Arthonia coriifoliae is a common and conspicuous species on its host in southernmost South America. Additional material investigated: Argentina: Tierra del Fuego: Tierra del Fuego Nat. Park, c. 16 km W of Ushuaia, E shore of Lago Roca, 54)48*S, 68)34*W, 1989, Wedin 1056b (UPS); as above, c. 9·5 km W Ushuaia, at Cascada Rio Pipo, 54)48*S, 68)30*W, 1989, Wedin 1087 (UPS); Wedin 1096 (UPS); Glaciar Martial, below the lower chair lift station, along the stream, 54)47*S, 68)23*W, 1989, Wedin 1117c (UPS); Lago Fagnano, Caberera Lago at the eastern end of Lago Fagnano, 1940, Santesson 1572 (UPS).—Chile: Region XII: Torres del Paine Nat. Park, c. 15 km WNW of the Park Administration, Rio Pingo, along Chorillo los Salmones, 51)07*S, 73)11*W, 1989, Wedin 1157 (UPS); Isla Navarino, 2·5 km SW of Puerto Williams, at small hydroelectric plant, 54)57*S, 67)4*W, 1989, Wedin 1202c (UPS); Wedin 1205b (UPS, IMI); as above, 6·5 km S Puerto Williams, in valley NE of Diente de Navarino, 55)59*S, 67)35*W, 1989, Wedin 1247 (UPS).

3. Arthonia flavicantis Wedin & Hafellner sp. nov. Species differt ab Arthonia badia et A. coriifoliae ascomatibus atris nitidisque et ascosporis soleiformibus. Typus: Argentina, Nequen: Nahuel Huapi Nat. Park, along the track from Puerto Blest to Laguna los Cantaros, 41)01*S, 71)50*W, on Pseudocyphellaria flavicans, 1989, Wedin 1774 (UPS—holotypus; isotypes will be distributed in Santesson, Fungi Lich. Exs.).

(Figs 1B, ascus; 2C, ascospores; 4A–B, hymenium)

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Description: Weakly parasitic on the thalli of Pseudocyphellaria flavicans and P. berberina. Apothecia (Fig. 4A) rounded, black and&shining, superficial, fleck-like, convex and often distinctly raised, often surrounded by a narrow discoloured zone, c. 0·25–0·65 mm diam., c. 40–50 ìm tall in section. Epithecium: c. (5–)10–15 ìm tall, dark brown, becoming greenish black in K. Hymenium c. 20–30 ìm tall, hyaline, I+ pale bluish, K/I+ blue. Hypothecium c. 5–10 ìm tall, hyaline, I+ pale bluish. Paraphysoids (Fig. 4B) indistinct, c. 1·5–2 ìm in the hymenium; in epithecium with thick dark brown apical caps, c. 3–5(–7) ìm thick; caps becoming greenish black in K. Asci (Fig. 1B) broadly clavate to almost pear-shaped, c. 20–27#11–14 ìm; ascus contents (perispore?) I+ red, no ring observed in K/I. Ascospores (Fig. 2C) c. 11–14#4·5–5·5 ìm, 1-septate, usually somewhat constricted at septum, soleiform, hyaline at first, with a thin perispore (c. 0·5 ìm thick), rapidly becoming brown and verrucose. Pycnidia not seen, but small bacilliform conidia observed in squash preparation of one specimen (c. 3·5#0·5 ìm). Notes: Arthonia flavicantis is an easily recognized species, with welldelimited, circular, fleck-like ascomata that have a glossy black colour, and with soleiform spores. It is a weak parasite only, causing little damage to the host, despite the often abundant infections. It may be similar to A. coriifoliae, which has larger, duller black apothecia, and to A. badia, which also has larger, dull, chestnut-brown apothecia. The last two species also differ in having oblong–ovoid ascospores. Arthonia plectocarpoides differs by forming distinctive galls, and by having somewhat larger, oblong–ovoid ascospores and larger asci. Arthonia flavicantis seems to be widespread in southernmost South America and is most commonly encountered on Pseudocyphellaria flavicans. Additional specimens investigated: Argentina: Nequen: Nahuel Huapi Nat. Park, along track from Puerto Blest to Cascada los Cantaros, on Pseudocyphellaria flavicans 41)01*S, 71)50*W, 1989, Wedin 1776b (UPS); Nahuel Huapi Nat. Park, at Cascada los Cantaros, on Pseudocyphellaria berberina, 1989, Wedin 1833b (UPS);—Chile: Region XII: Isla Ruiz, B. Corbeta Papudo, on Pseudocyphellaria flavicans, 50)22*S, 75)20*W, 1969, Imshaug 44087 (BM).

4. Arthonia maculiformis Wedin & Hafellner sp. nov. Species distincte parasitica. Infectiones ut in Arthonia subconvenienti sed ab ea differt ascosporis latioribus. Typus: New Zealand: North Island: Wellington: Tongariro Nat. Park, vicinity of Whakapapa Village, along Whakapapanui Stream, on Pseudocyphellaria glabra, 39)11*S, 175)32*E, 1990, Wedin 2298 (UPS—holotypus; AK, BM, GZU—isotypi).

(Figs 2D, ascospores; 5A, hymenium) Description: Parasitic on the thallus of Pseudocyphellaria glabra and P. homoeophylla, causing extensive areas of discoloured, darkened tissue. In younger infections (very clearly visible in Wedin 2539) dark, dichotomously branching hyphae, obviously belonging to the Arthonia, are visible towards the edges of the discoloured patches. Apothecia (Fig. 5A) evenly distributed in the central parts of the infected areas, dark brown to black, irregular to&rounded, fleck-like, flattened, c. 0·1–0·5 mm in diam., in section c. 35–45 ìm tall. Epithecium c. 5–11 ìm tall, strongly pigmented, dark brown; becoming

F. 5. A–C, Longitudinal sections of hymenia; A, Arthonia maculiformis, in water (isotype, GZU); B, A. minuta, in cotton blue/interference contrast (Wedin 1192); C, A. pelvetii, in water/interference contrast (Hafellner 33827). Scale=25 ìm.

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greenish black in K. Hymenium c. 20–35 ìm tall, I+ red, K/I+ blue. Hypothecium c. 5–11 ìm tall, hyaline. Paraphysoids c. 0·5–1·5 ìm wide in the hymenium, hyaline; in the epithecium branching and extending periclinally above the asci, up to 2·5 ìm wide, brown-walled, strongly encrusted by brownish pigment, no apical caps observed. Asci pyriform to subglobose, c. 15·5–25·5#13·5–16·5 ìm, no amyloid apical ring seen in K/I; 8-spored. Ascospores (Fig. 2D) c. 13–16·5#5–6·5 ìm, 1-septate, constricted at septum, oblong–ovate, hyaline at first, with a thin perispore (c. 0·5 ìm thick), rapidly becoming brown and verrucose; perispore I+ red. Pycnidia not seen. Notes: Arthonia maculiformis is a very distinctive and clearly parasitic species that causes extensive areas of discoloured, darkened tissue on the host. It is at present known only from New Zealand. The two hosts, P. glabra and P. homoeophylla, share several lichenicolous fungi, among them another parasitic Arthonia species, A. pseudocyphellariae, which is easily separated from A. maculiformis by having bright red, K+ violet apothecia. The epithecium in A. maculiformis is strongly pigmented and may at a glance appear to be made up of capitate paraphysoid tips, but which in K are clearly seen to be non-capitate. Additional material investigated: New Zealand: North Island: Wellington: Tararua State Forest, along Mt Holdsworth Track, between Mountain House and Powell Hut, on Pseudocyphellaria homoeophylla, 40)54*S, 175)26*E, 1990, Wedin 2483 (UPS, AK, M); as above, Wedin 2487 (UPS, BM, GZU); Wedin 2492a (UPS, AK, IMI); as above, Tararua State Forest Park, along track from Kiriwhakapapa entrance to Te Mira peak, at takeoff to Cow Creek Hut, on Pseudocyphellaria homoeophylla, 40)47*S, 175)30*E, 1990, Wedin 2539 (UPS, BM).

5. Arthonia minuta Wedin & Hafellner sp. nov. Species non distincte parasitica differt praeterea ab Arthonia subaggregata ascosporis maioribus et ab Arthonia santessoniana ascomatibus elevatis aliquot pallidioribus. Typus: Argentina, Tierra del Fuego: Glaciar Martial, below the lower chair lift station, along a stream, 54)47*S, 68)23*W, 1989, Wedin 1111b (UPS—holotypus; BCRU, BM, GZU—isotypi).

(Figs 2E, ascospores; 5B, hymenium.) Description: Commensalistic on the thallus of Pseudocyphellaria coriifolia. Apothecia (Fig. 5B) scattered, dark brown, rounded, lecideoid, sessile to somewhat stiped, somewhat flattened, c. 0·07–0·1 mm in diam., in section c. 70–100 ìm tall. Epithecium c. (5–)10–15 ìm tall, brown, changing to greenish black in K. Hymenium c. 25–40 ìm tall, hyaline, I+ red, K/I+ blue. Hypothecium c. 15–35 ìm tall, pale reddish brown, becoming pale greenish in K. Paraphysoids c. 1·5–2 ìm wide in the hymenium, hyaline or somewhat brownish; in epithecium more richly branching and extending periclinically above the asci, up to 3 ìm wide, brown-walled, no apical caps observed. Asci broadly clavate to subglobose, c. 22–33#12–19 ìm; with a distinct amyloid apical ring in K/I; 8-spored. Ascospores (Fig. 2E) c. 9·5–12(–14)#4–5·5 ìm, 1-septate, constricted at the septum, soleiform to narrowly ellipsoid, hyaline; no perispore observed. Pycnidia not found.

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Notes: Arthonia minuta is common on Pseudocyphellaria coriifolia, but it easily overlooked due to the minute size of the apothecia. Most specimens have been found in collections of other lichenicolous fungi, as the host harbours a rich variety of such fungi. Arthonia minuta, A. santessoniana and A. subaggregata are similar to A. epiphyscia and related taxa. Arthonia epiphyscia, a common fungus on species of Physcia, differs from the two former species by producing black, convex apothecia that are normally clearly aggregated, and from A. subaggregata by having larger spores. Arthonia minuta is known only from southernmost South America. Additional material investigated: Argentina: Tierra del Fuego: Glaciar Martial, below the lower chair lift station, along a stream, 54)47*S, 68)23*W, 1989, Wedin 1115b (UPS); Wedin 1117b (UPS).—Chile: Region XII: Magallanes, Peninsula Brunswick, c. 6 km W of Punta Arenas, Forest reserve ‘ Magallanes ’, at Rio las Minas, 53)08*S, 73)01*W, 1989, Wedin 1192b (UPS); Isla Navarino, 2·5 km SW of Puerto Williams, at small hydroelectric plant, 54)57*S, 67)41*W, 1989, Wedin 1202b (UPS); as above, 6·5 km S of Puerto Williams, in valley NE of Diente de Navarino, 55)59*S, 67)35*W, 1989, Wedin 1213c (UPS, BM).

6. Arthonia pelvetii (Hepp) H. Olivier Bull. Acad. Internat. Géogr. Bot. sér. 3, 16: 193 (1906).—Celidium pelvetii Hepp, Flechten Europas no. 372 (1857); type: [France, Normandy, Calvados] ‘ ad arborum truncus cica Vire leg. Pelvet ’, Schaerer, Lich. Helvet. exs. no. 558 [sub Sticta aurata] (UPS—lectotype, selected here; BM—isolectotypes).—Arthonia vagans subsp. pelvetii (Hepp) Almq., K. svenska VetenskAkad. Handl. 17(6): 57 (1880). Sticta aurata b abortiva Schaer., Enum. Crit. Lich. Eur.: 33 (1850); type: [France, Normandy, Calvados] Vire, 1840, Pelvet (G—lectotype, selected here; UPS—isolectotype). Exsiccata: Hepp, Flechten Europas no. 372 [sub Sticta aurata]; Flechten Europas 589 [sub Celidium pelvetii], Schaerer, Lich. Helvet. Exs. no. 558 [sub S. aurata]; Zahlbr., Lich. Rar. Exs. no. 298 [sub S. aurata], Santesson, Fungi Lich. Exs. no. 152.

(Figs 5C, hymenium; 6A, ascospores) Notes: Arthonia pelvetii is found growing as a commensal or weak parasite on Pseudocyphellaria aurata, and is quite common in Macaronesia. It is characterized by brownish, often relatively pale, fleck-like ascomata, which in section (Fig. 5C) are pale greenish brown to almost hyaline, and an epithecium consisting of erect and&unbranched paraphysoid apices lacking apical caps and almost entirely lacking pigmentation; the very pale greenish brown pigmentation becomes more greenish in K. The spores (Fig. 6A) are hyaline, c. 11–13·5#4·5–5·5 ìm. Asci (Fig. 5C) broadly clavate to subglobose, c. 26–35#14·5–17 ìm, no K/I+ blue ring seen. Hymenium I+ red, K/I+ blue. Pycnidia not seen. Arthonia stictaria is probably closely related but differs by having a very distinct epithecium where the paraphysoid tips are branched, strongly pigmented and more or less extending laterally above the asci. Nomenclatural notes: The name Celidium pelvetii is published in Hepp’s schedae (Hepp 1857) together with no. 372, not with no. 589 as appears to be generally assumed. In the specimens of no. 372 investigated, the lichenicolous fungus is only present on a relatively small piece in E. In three specimens in G, two in UPS and one in BM, no A. pelvetii is present. As Hepp himself in

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F. 6. Ascospores. A, Arthonia pelvetii (Santesson 26860); B, A. plectocarpoides (holotype); C, A. pseudocyphellariae (Wedin 4992); D, A. santessoniana (holotype); E, ‘A.’ semi-immersa (holotype). Scale=10 ìm.

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connection with the protologue refers to ‘ black warts on the thallus ’ mentioned by Schaerer (1850) and cites Schaerer, Lich. Helvet. no. 558, specimens in this latter exsiccatum with the lichenicolous fungus present represent syntypes. Two specimens of this exsiccata number are present in UPS, only one of them with the lichenicolous Arthonia richly developed on a large thallus; that specimen is therefore here designated lectotype. A richly infected specimen annotated as Sticta aurata b abortiva Schaer., and with the name and place of publication is present in Schaerer’s herbarium in Geneva. It was collected by Pelvet 1840 in Vire, France and is here designated lectotype. The status of Pelvet’s specimen in UPS, also from Vire but without a date, is somewhat uncertain but is most probably a duplicate of the specimen in G. Additional specimens investigated: France: Bretagne: Finistère; forest of Coatloch, des Abbayes [Zahlbr., Lich. Rar. Exs. no. 298] (UPS); Normandy: Manche; Briequebec, Pelvet [Hepp, Flechten Europas no. 598] (E, G, UPS); Briequebec, Lenormand [Hepp, Flechten Europas no. 372] (E);—Portugal: Azores: St. Jorge, 1937, Persson (UPS); Madeira: 1865, Mandon (BM); Between Ponta del Sol and Porto Moniz, Rabacal, 1992, Diederich 4923 (hb. Died.): Road between Ribera Brava and S. Vicente, 2 km N of Encumeada, 1992, Diederich 4869 (hb. Died.); Queimadas c. 5 km ober Santana, 32)47*N, 16)54*W, 1990, Hafellner & Hafellner 27078 (GZU, BM); as above, 1992, Diederich 4847 (hb. Died.); as above, c. 2 km N unter der Passhöhe Boca de Encumeada, 32)45*N, 30)01*W, 1990, Hafellner & Hafellner 27677 (GZU); as above, Ribeiro Frio, 32)43*N, 16)53*W, 1990, Hafellner & Hafellner 26961; as above, 1992, Etayo 5521 (hb. Died.); as above, c. 2 km oberhalb von Ribeiro Frio, 32)43*N, 16)53*W, 1990, Hafellner & Hafellner 26961 (hb. Haf.); Beira litoral, Mt Bucace, c. 20 km NNE of Coimbra, between Capela de Sto Antao and Crus Alta, 1980, Löfgren 827 (UPS);—Spain: Canary Islands: Tenerife, Las Montanas de Anaga, near El Bailadero, 1976, Santesson 26860 (UPS); as above, Macizo de Teno, Monte del Agua, 28)19*N, 16)48*W, Hafellner 33752 (hb. Haf.); as above, am Fussveg von Erjos nach El Palmar, 1975, Agerer & Blanz (GZU); La Gomera, 10 km SSW ober Las Rosas an der Strasse nach La Laguna Grande, 17)14*N, 28)07*W, 1991, Hafellner & Hafellner 32825 (GZU, hb. Haf.); as above, La Montaneta E ober El Cedro, am Höhenrücken SW vom Gipfel, 29)07*N, 17)12*W, Hafellner & Hafellner 33827 (hb. Haf.).

7. Arthonia plectocarpoides (S. Kondr. & D. J. Galloway) Wedin & S. Kondr. Lichenologist 29: 97 (1997). Dactylospora plectocarpoides S. Kondr. & D. J. Galloway [as ‘ S. Kondr., D. J. Galloway & D. Hawksw. ’, see Wedin & Kondratyuk 1997]. Acta Bot. Fennica 150: 95 (1994); type: Chile, X Region, Rio Enco and roadside between Choshuenco and Enco, 1986, Coppins, Galloway, Guzman & James 8111 (BM—holotype; E—isotype [not seen]).

(Figs 6B, ascospores; 7A–B, hymenium; Wedin & Kondratyuk 1997, fig. 1A–C, ascus, paraphysoid, ascospores) Description: Cecidogenous (gall forming) on Pseudocyphellaria scabrosa. Apothecia scattered, dark brown to black, matt, fleck-like, superficial, distinctly rounded and convex, and covering distinctly raised galls (Fig. 7A), c. 0·5–2 mm diam., in section c. 80–120 ìm tall; galls&constricted at base. Epithecium c. 10–15 ìm tall, dark brown, changing to greenish black in K. Hymenium c. 45–55 ìm tall, hyaline, I+ blue, K/I+ blue. Hypothecium c. 20–45 ìm tall, hyaline, I+ bluish. Paraphysoids (Fig. 7B) c. 1·5–2(–3) ìm in the hymenium, hyaline; in the epithecium erect, apices thickened, with a granular brown pigment and with distinct dark brown caps, c. 4–6(–7) ìm

F. 7. A–B, Arthonia plectocarpoides (Santesson 3733); A, longitudinal section of hymenium, note the thick gall-formation induced in the host tissue, in water/interference contrast; B, paraphysoids and asci, in water/interference contrast; C, A. santessoniana (holotype), longitudinal section of hymenium, in water/interference contrast; D, A. subaggregata (holotype), longitudinal section of hymenium and pycnidium, in water. Scales: A, 100 ìm; B–D 25 ìm.

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wide, caps becoming greenish black in K. Asci clavate to broadly clavate, c. 40–45#18–25 ìm; no ring-structure visible in K/I, 8-spored. Ascospores (Fig. 6B) c. (11–)13–15(–17)#4–6(–6·5) ìm, 1-septate, somewhat constricted at septum, oblong–ovoid, hyaline and smooth with a distinct perispore (c. 0·5–1 ìm thick in water) but later becoming brown and warted; perispore I+ red. Pycnidia not seen. Notes: As pointed out in the original description (Kondratyuk et al. 1994) the galls formed by this species may look very similar to Plectocarpon-galls. The genus Plectocarpon, however, belongs to the Opegraphaceae (Diederich & Etayo 1994) and is easily recognized by the multilocular stromatic ascomata, the distinct, richly branched and anastomosing, net-like hamathecium and the clavate Opegrapha-type asci, as in Plectocarpon linitae, which is treated below. Wedin & Kondratyuk (1997) made the necessary combination of this distinct fungus in Arthonia, and provided a brief description and illustrations. Another species of Arthonia on the same host, A. santessoniana, is described below, and differs from A. plectocarpoides in the lecideoid to somewhat fleck-like, smaller apothecia, smaller asci with a distinct K/I+ ring structure, the smaller, completely hyaline spores and the non-capitate paraphysoids. The other species with capitate paraphysoids and an I+ blue hymenium, A. badia, A. coriifoliae and A. flavicantis, differ in not forming distinct galls (A. coriifoliae and A. flavicantis may, however, have raised apothecia), and in having&smaller spores and asci. Arthonia plectocarpoides is at present known only from a very small area in the Valdivian rainforest region of Chile. It is the first species of Arthonia known to form distinctive galls. Additional specimens examined: Chile: X Region: 11·4 km SW of Choshuenco near Rio Enco, 72)8*W, 39)53*S, 1986, Coppins, Galloway, Guzman & James 8052 (BM); Lago Rinihue, Enco, 1940, Santesson 3666 (UPS); 3733 (UPS, GZU).

8. Arthonia pseudocyphellariae Wedin Lichenologist 25: 301 (1993); type: New Zealand, Gisborne, Urewera Nat. Park, 1992, Wedin 4056 (UPS—holotype; Santesson, Fung. Lich. Exs. no. 153—isotypes). Exsiccata: Santesson, Fung. Lich. Exs. no. 153.

(Fig. 6C, ascospores; Wedin 1993, figs 1–2, infections, hymenium, asci, paraphysoids and spores; Grube et al. 1995, fig. 2a, ascospores) Notes: This is a very characteristic species, the only species treated here having K+ violet apothecia, which grows on Pseudocyphellaria glabra, P. homoeophylla and P. multifida. It is clearly parasitic, forming more or less aggregated orange-red ascomata within patches bordered by a necrotic zone. All parts of the ascomata are K+ strongly violet, and the one-septate soleiform ascospores finally become brown and verrucose. Arthonia pseudocyphellariae was described and illustrated by Wedin (1993) and discussed and illustrated by Grube et al. (1995). It was originally described from New Zealand, Tasmania and Juan Fernandez Islands, and we take the opportunity to here report an additional locality in New South Wales, and some additional localities in New Zealand.

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Additional material investigated: Australia: New South Wales: 56 km WSW Gloucester, Barrington Tops Nat. Park, NW Barrington Guesthouse, along Carreys Peak Trail, on Pseudocyphellaria glabra, 32)04*S, 152)28*E, 1990, Wedin 3456 (UPS, CBG, H, HO).—New Zealand: Nelson: N–W Nelson Forest Park, Peel Range, track from Cobb Reservoir to Lake Peel, 41)08*S, 172)36*E, 1995 Wedin 4989 (UPS); as above, S of Balloon Hut, 41)10*S, 172)37*E, 1995, Wedin 4992 (UPS, BM); Otago: E of Milford Sound, 44)40*, 168), 1992, Cernic (hb. Haf. 32779); Stewart Island: Ulva Island, along Nature Track, 46)53*S, 168)07*E, 1995, Wedin 4901 (UPS).

9. Arthonia santessoniana Wedin & Hafellner sp. nov. Species differt ab Arthonia minuta ascomatibus obscurioribus minus elevatis et ab Arthonia subaggregata ascomatibus dispersis et ascosporis aliquot maioribus. Typus: Argentina: Tierra del Fuego; Lago Fagnano, Caberera Lago at the eastern end of Lago Fagnano, on Pseudocyphellaria scabrosa, 1940, Santesson 7973 (UPS—holotypus; GZU—isotypus).

(Figs 6D, ascospores; 7C, hymenium) Description: Commensalistic or weakly parasitic on Pseudocyphellaria fimbriata, P. montagnei and P. scabrosa. Apothecia (Fig. 7C) scattered, black to (occasionally) dark brown, rounded to somewhat irregular in outline, superficial, lecideoid to somewhat fleck-like, c. 0·08–0·3 mm diam., c. 55– 75 ìm tall in section. Epithecium c. 5–10 ìm tall, dark brown, becoming greenish black in K. Hymenium c. 25–30 ìm tall, hyaline, I+ red, K/I+ blue. Hypothecium c. 20–25 ìm tall, pale reddish brown. Paraphysoids c. 1·5–3 ìm wide in the hymenium, hyaline; in the epithecium brown-walled, richly branched and extending periclinally above the asci; apices not distinctly thickened, c. 2–3 ìm wide. Asci broadly clavate, c. 23–35#14–19 ìm; with a distinctly amyloid ring in K/I; 8-spored. Ascospores (Fig. 6D) c. 11–14#4·5– 6 ìm, 1-septate, constricted at septum, ellipsoid to oblong–ovoid, upper cell usually somewhat wider than the lower, hyaline, with a thin (<0·5 ìm) perispore. Pycnidia not seen. Notes: Arthonia santessoniana is anatomically similar to A. minuta and A. subaggregata, but differs in the much larger apothecia and somewhat larger ascospores. In addition, it differs from A. subaggregata in the scattered apothecia, and from A. minuta in the colour of the apothecia, which are paler and brown in the latter. The other Arthonia species occurring on Pseudocyphellaria scabrosa, A. plectocarpoides, is gall-inducing, has ascospores that eventually become brown, and has erect paraphysoids with distinct caps. Arthonia santessoniana is known only from scattered collections from Chile and New Zealand. The material studied seems uniform, despite growing on three different host species, and the species may well be much more common than the few collections suggest. Additional material investigated: New Zealand: Canterbury: Lewis Pass, 1992, Cernic (GZU); The Boyle, c. 20 km E of Lewis Pass, 1992, Cernic (GZU).

10. ‘ Arthonia ’ semi-immersa Wedin & Hafellner sp. nov. Species differt ab aliis specibus lichenicolis generis ascomatibus concretis semiimmersis, hymenio iodo non reagenti et paraphysibus parce ramosis. Typus: Argentina: Tierra del Fuego: Steiler Hang N Passo Garibaldi, gegenüber Lago Escondido, 1989, Poelt (GZU—holotypus; UPS—isotypus).

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(Figs 1E, asci and hamathecial filaments; 6E, ascospores; 8B–C, hymenium) Description: Parasitic on Pseudocyphellaria sp. Apothecia (Fig. 8B–C) at first&immersed in the thallus, later rupturing the host cortex, and finally superficial and&sessile; often produced in short rows of 3–5 apothecia in the cortical fissures; pale to dark brown, rounded, lecideoid, c. 0·1–0·2 mm diam., c. 80–100 ìm tall in section; all parts I" and K/I". Epithecium c. 10 ìm tall, hyaline to brownish, becoming paler brown in K. Hymenium c. 60–70 ìm tall, hyaline to pale brown. Hypothecium c. 15–20 ìm tall, hyaline. Paraphysoids (Fig. 1E) very sparingly branching, with few anastomoses, thick, erect, c. 2–4 ìm thick in the hymenium; distinctly thickened in the epithecium, not extending laterally above the asci, up to c. 7 ìm thick, no apical caps seen. Asci (Fig. 1E) fissitunicate, narrowly clavate, c. 50–60#13–15 ìm, no ring visible in K/I. Ascospores (Fig. 6E) c. 14·5–18#5–7 ìm, 1-septate, oblong–ovoid, hyaline; no perispore observed. Pycnidia not seen. Notes: ‘ Arthonia ’ semi-immersa is clearly not an Arthonia s. str., and deviates considerably from the other species treated here in having elongated, narrowly clavate asci, a completely I" hymenium and stout, erect hamathecial filaments that are very little branched. The placement of this species in Arthonia is therefore provisional, pending a revision of the delimitation of the genus. ‘ Arthonia ’ semi-immersa differs from the lecanoralean Corticiruptor abeloneae, which likewise has ascomata&immersed in the host tissue, by having a completely I" hymenium, in having larger, one-septate ascospores, and in having fissitunicate asci. It is hitherto known only from the type collection from the Argentinian part of Tierra del Fuego. 11. Arthonia stictaria Nyl. Flora 50: 440 (1867); type: ‘Supra Stictae auratae [Pseudocyphellaria poculifera (Müll. Arg.) D. Galloway & P. James] thallum in Nova Zelandia’, Knight (H-NYL—lectotype, selected here; BM, 3 isolectotypes; UPS, isolectotype).

(Figs 9A, ascospores; 8A, hymenium) Description: Arthonia stictaria is weakly parasitic or commensalistic on Pseudocyphellaria poculifera, and is at the moment known only from the type, collected in New Zealand. It has dark brown, fleck-like ascomata, a distinct, greenish brown, c. 8–10 ìm tall epithecium consisting of branched paraphysoid ends (Fig. 8A), &extending laterally above the asci; no paraphysoidal caps seen, but some ends are&swollen, c. 2·5–3·5 ìm diam., and the pigment (which becomes greenish black in K) often extends downwards along the paraphysoids in the hymenium. The asci are clavate, c. 22·5–28#10–12 ìm; at least in some a minute K/I+ ring was seen, and the hymenium reacts I+ red, K/I+ blue. The ascospores (Fig. 9A) are hyaline, oblong–ovoid, c. 11–13#4–5·5 ìm. Pycnidia not seen. Notes: Arthonia stictaria has for a long time been assumed to be a synonym to A. pelvetii, which is clearly very similar, but the latter differs by having an

F. 8. A, Arthonia stictaria (isolectotype, BM); longitudinal section of hymenium, in water/ interference contrast; B–C, ‘ A. ’ semi-immersa (holotype); B, hamathecial filaments and asci, in lactic blue; C, longitudinal section of hymenium, in lactic blue/interference contrast; D, A. subconveniens (isotype, GZU), longitudinal section of hymenium, in lactic blue/interference contrast. Scale=25 ìm.

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F. 9. Ascospores. A, Arthonia stictaria (isolectotype, BM); B, A. subaggregata (Wedin 1031b); C, A. subconveniens (isotype, UPS). Scale=10 ìm.

indistinct, almost unpigmented epithecium consisting of erect, &unbranched paraphysoid ends. It is still known only from the original collection, material collected by Knight in New Zealand, and original specimens have been found in H-NYL, UPS and in BM. The material in H-NYL is rich and abundantly infested with the Arthonia, and is here designated lectotype. The specimens in BM were reported on (as A. pelvetii) by Kondratyuk & Galloway (1994). 12. Arthonia subaggregata Wedin & Hafellner sp. nov. Species differt ab Arthonia minuta ascomatibus aggregatis et ascosporis minoribus et ab A. santessoniana ascomatibus aggregatis minoribus. Typus: Chile: Region XII: Peninsula Brunswick, c. 6 km S Fuerte Bulnes, close to the seashore S of Rio San Juan, on Pseudocyphellaria hirsuta, 53)40*S, 70)57*W, 1989, Wedin 1253c (UPS—holotypus; BM, GZU—isotypi).

(Figs 1D, asci and paraphysoids; 7D; hymenium and pycnidium; 9B, ascospores) Description: Weakly parasitic on the thallus of Pseudocyphellaria hirsuta and P. dubia. Apothecia (Fig. 7D)&aggregated, rarely somewhat confluent, black, rounded to somewhat uneven, lecideoid, superficial, convex to somewhat flattened, c. 0·08–0·20 mm wide, c. 75–80 ìm tall in section. Epithecium

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c. 10–15 ìm tall, dark greenish brown, with a K" granular pigment. Hymenium c. 25–30 ìm tall, hyaline, I+ strongly red, K/I+ blue. Hypothecium c. 20–30 ìm tall, hyaline to pale brownish, no change of colour in K. Paraphysoids (Fig. 1D, 7D) c. 2–3 ìm in hymenium, hyaline; in epithecium brown-walled, richly branched, c. 3–4 ìm thick, no apical caps observed. Asci (Fig. 1D) broadly clavate, c. 22–35#13–17 ìm, in K/I at least sometimes with a minute amyloid ring; 8-spored. Ascospores (Fig. 9B) c. 8–10·5#3·5– 4·5 ìm, 1-septate, constricted at septum, upper cell usually distinctly shorter and broader than the lower, hyaline; no perispore observed. Pycnidia (Fig. 7D) occasionally observed adjacent to the ascomata, c. 55 ìm in section, superficial, wall with greenish-brown pigment. Conidia c. 4–5#1–1·5 ìm, rod-shaped. Notes: Arthonia subaggregata differs from the other lichenicolous Arthonia-species known from the area in the small ascospore size. The ascomata are often more or less aggregated, sometimes somewhat confluent, and the infected areas are usually somewhat discoloured, thus indicating a weakly parasitic habit of the species. Arthonia subaggregata may be similar to A. minuta, which differs in being commensalistic, in having scattered apothecia, and in having somewhat larger ascospores. Arthonia subaggregata is known from scattered collections from southernmost South America. Additional material investigated: Argentina: Tierra del Fuego: c. 4 km NW of Ushuaia, Glacial Martial, below upper end station of chairlift, on Pseudocyphellaria dubia, 54)47*S, 68)23*W, 1989, Wedin 1031b (UPS).—Chile: Region XI: Aisen, Coyhaique, Cerros Divisaderos (Cordon de Bella Vista), on Pseudocyphellaria hirsuta, 1949, Santesson 4462 (UPS).

13. Arthonia subconveniens Nyl. Flora 50: 440 (1867); type: Brazil: Widgren (H—holotype, not seen; Santesson, Fung. Lich. Exs. no. 154—isotypes) ?Arthonia ricasoliae Müll. Arg., Flora 70: 424 (1887); type: Australia; Knight, ‘ In thallo Ricasoliae Hartmanni in Australiae territorio Queensland ’ (G—two syntypes). Exsiccata: Santesson, Fung. Lich. Exs. no. 154.

(Figs 9C, ascospores; 8D, hymenium) Description: Arthonia subconveniens has narrower ascospores than the other species with fleck-like ascomata and an I+ red hymenium treated here. The apothecia are dark brown to black, &circular in outline and surrounded by an irregular, brownish zone, indicating a weakly parasitic habit. The hypothecium is pale brownish, and the pale brownish epithecium is composed of branched paraphysoids without apical caps. The hymenium reacts I+ red and K/I+ blue. A minute K/I+ blue ring was observed in at least some young asci. The asci are c. 22–30#14–17 ìm, and (6–)8-spored; the ascospores (Fig. 9C) are one-septate, c. 13–15#4 ìm in the type of A. subconveniens, and (8–)11– 13#3 ìm in the type of A. ricasoliae, narrowly oblong to soleiform. No perispore or pycnidia were observed. Notes: Arthonia subconveniens grows on Lobaria peltigera (‘ Ricasolia dissecta ’) in Brazil and is known only from the type collection. Arthonia ricasoliae is, with

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some hesitation, considered to be conspecific with A. subconveniens. More material is needed to fully evaluate its status, as both taxa are known only from the type collections, and it is difficult to judge the significance of the difference in ascospore size on the basis of the very limited and old material available. The type of A. ricasoliae (also growing on a species of Lobaria) has somewhat smaller ascospores to A. subconveniens, and in other respects, the specimens are very similar. Arthonia fuscopurpurea, a relatively common species on Peltigera, which is similar in having soleiform ascospores, differs by having browner (often reddish brown) apothecia and possibly also in having somewhat larger ascospores, although the ascospore range of A. subconveniens is based on very few measurements. Arthonia fuscopurpurea usually produces abundant pycnidia along the edges of the ascomata; and has bacilliform conidia, c. 3·5–5#1 ìm. Excluded Species 14. Plectocarpon linitae (R. Sant.) Wedin & Hafellner comb. nov. Arthonia linitae R. Sant., Thunbergia 6: 1 (1988); type: Sweden, Torne Lappmark, Abisko, 3.viii.1947, Santesson s. n. (UPS—holotype; Santesson, Fung. Lich. Exs. no. 101—isotypes). Exsiccata: Santesson, Fung. Lich. Exs. nos 101 and 128.

(Fig 10A–B) Description: Plectocarpon linitae is commensalistic on the thallus of Lobaria linitae in the Scandinavian mountains (Santesson 1988) and in North America (Esslinger & Egan 1995). It has brownish, fleck-like, multilocular ascomata (Fig. 10A), which under the dissecting microscope are seen to be built up of small, elongated lirellae. The hypothecium is brown, and the epithecium is unevenly developed and composed of patches of brownish pigmentation. The hymenium is I+ red and K/I+ blue and the net-like hamathecium is composed of distinct, richly branched and anastomosing filaments. The clavate asci (c. 33·5–47#11–15·5 ìm) have a distinct K/I+ blue ring, and the spores are 3-septate [c. 14·5–19(–21) ìm] with a very distinct perispore. Pycnidia (Fig. 10B) are commonly found immersed in the ascostroma, and produce slightly pointed, &narrowly ellipsoid microconidia (c. 3–4#1 ìm). Notes: This species clearly belongs to Plectocarpon sensu Diederich & Etayo (1994). Plectocarpon linitae is not the only Plectocarpon with non-carbonized ascostroma. In P. scrobiculatae Diederich & Etayo the stromatic plectenchyma between the asci-producing parts is also typically pale. Most species of Plectocarpon induce distinct galls, but several (including P. macaronesiae Diederich et al.) are, as P. linitae, not cecidogenous. Additional specimen investigated: Sweden: Torne Lappmark: Abisko, 16.viii 1947, Santesson (UPS); as above, 1986, Santesson 31646b [Santesson, Fung. Lich. Exs. no. 128] (GZU).

15. Corticiruptor abeloneae (P. M. Jørg.) Wedin & Hafellner Corticiruptor Wedin & Hafellner gen. nov. (Lecanorales, Cladoniineae) Genus ad Lecanorales pertinet. Apothecia (speciei typicae) ex cortice superiori hospidis erumpentia, minuta, pallida. Excipulum reductum. Asci tholis cum tubis iodo amyloideis instructi.

F. 10. A–B, Plectocarpon linitae, in water/interference contrast (isotype, GZU); A, longitudinal section of hymenium; B, pycnidium; C–E, Corticiruptor abeloneae (Hafellner 33827); C, longitudinal section of apothecium, in water/interference contrast; D, primordia of apothecia developing below the cortex of the host, in water/interference contrast; E, longitudinal section of apothecium, in lactic blue. Scale=25 ìm.

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Dehiscentia rostrata. Paraphyses frequenter ascis breviores, parce ramosae. Ascosporae hyalinae, non distincte halonatae, in specie typica unicellulares. Genus differt a generibus Micareacearum apotheciis inundatis et paraphysibus haud anastomosantibus etiam biologia. Typus: Corticiruptor abeloneae (P. M. Jørg.) Wedin & Hafellner.

Etymology: from cortex (Latin, feminine)=bark, outer layer, and ruptor (Latin, masculine)=somebody who breaks or hurts, because the type species Corticiruptor abeloneae breaks through the upper cortex of the host, which gives an external appearance similar to the leotialean Corticifraga fuckelii (Rehm) D. Hawksw. & R. Sant. Notes: No other lecanoralean genus including lichenicolous species, characterized by the set of characters present in Corticiruptor abeloneae, is known at present. The only genus containing lichenicolous species and exhibiting asci with tube structures is Scutula. However, all known Scutula species have sessile apothecia with well-developed biatorine exciples, distinctly septate ascospores, and characteristic anamorphs (Triebel et al. 1997). Consequently, we found it necessary to describe a new genus to accommodate this distinct fungus. The classification of this new genus in Lecanorales is clear from the construction of the ascal wall. However, Corticiruptor cannot be assigned to a family with certainty at present. Asci with similar features are known in the genera of Micareaceae but lichenicolous taxa are so far not known with certainty in this family, with the possible exception of Scutula, placed in the Micareaceae with a question mark by Hafellner et al. (1993) but indicated to be related to the Mycobilimbiaceae (sensu Hafellner 1984) by Triebel et al. (1997). The lack of an exciple in mature apothecia as well as the characters of the ascus tip could perhaps suggest a closer relationship with Micarea itself, but we regard this as unlikely, as other characters, such as those of the paraphyses, differ considerably. Corticiruptor abeloneae (P. M. Jørg.) Wedin & Hafellner comb. nov. Arthonia abeloneae P. M. Jørg. [‘ abelonae ’], Nova Hedw. 18: 338 (1970); type: Norway, Hordaland, Møkster, 1967, Bjørnstad (UPS—2 isotypes).

(Figs 10C–E; 11) Description: Commensalistic on thalli of the cyanobacterial morph of Sticta canariensis (‘ S. dufourii ’). Vegetative hyphae not discernible in the host thallus, neither reacting with I (Lugol) nor metachromatic (Toluidine Blue). Apothecia (Fig. 10C–E) often somewhat aggregated on the lobes of the host, hyaline to slightly brownish (darker brown only when old), rounded, developing below the surface of the upper cortex of the host when young, but later on breaking through the cortex, c. 100–200 ìm in diam. Exciple missing, only a few free hyphae (?outermost paraphyses) mark its lateral position. Epithecium absent. Hymenium (Fig. 11) c. 50–60 ìm tall, hyaline; not inspersed with oil droplets; hymenial gel not amyloid. Hypothecium c. 15–25 ìm tall, hyaline to slightly brownish, visible as textura globulosa with conglutinated walls in longitudinal section. Paraphyses (Fig. 11) c. 2·0–2·5 ìm thick, &unbranched, apical cells

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Corticiruptor abeloneae (Hafellner 33827); different developmental stages of asci, paraphysis and ascospores (in Lugol’s solution). Scale=10 ìm.

not enlarged and not distinctly pigmented. Asci (Fig. 11) clavate–narrowly clavate, c. 45–60#10–15 ìm, ascal wall and gel I+ blue; tholus I+ blue, with a distinct, central tube structure; staining of the tube fading towards the edge; 8-spored; dehiscence rostrate. Ascospores (Fig. 11) c. 10–14#3–4·5 ìm, simple, hyaline, without distinct perispore. Pycnidia not observed. Notes: Corticiruptor abeloneae is an apparently rare but very distinct fungus. It is easily recognized by the small, pale to occasionally dark brown ascomata, which are immersed in the upper side of the host thallus. Corticiruptor abeloneae differs from the other species with&immersed ascomata treated here (‘ Arthonia ’ semi-immersa) in the lecanoralean, I+ blue asci and the smaller spores. Both species have relatively narrowly clavate asci

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compared with most other species treated here, which have&broadly clavate to pear-shaped or subglobose asci. We have been able to find only non-septate ascospores in C. abeloneae, although in the original description the ascospores are reported to be 1–2 septate. Corticiruptor abeloneae is known from Norway, France, and the Canary Islands (Jørgensen 1970), and Scotland (Hitch 1994). Additional specimens investigated: U.K.: Scotland: Westerness, Morvern, Drimnin, valley of Abhain Mhungasdail, 1992, Coppins 14901 (BM).—Spain: Canary Islands: Tenerife, Macizo de Anago, along the road to Cabezo del Tejo, 1989, Hafellner 36486 (GZU, duplicates will be distributed in: Santesson, Fungi. Lich. Exs.). Rolf Santesson is gratefully thanked for making available his rich collections of lichenicolous fungi from Chile and Argentina, and Brian Coppins kindly supplied an additional specimen of Corticiruptor abeloneae. Martin Grube commented on the manuscript, and Pat Wolseley kindly corrected the English. The herbaria sending loans are gratefully acknowledged. MW acknowledges support from Anna och Gunnar Vidfelts fond för biologisk forskning (Gothenburg), The Royal Swedish Academy of Sciences (P. F. Wahlbergs Fond, Hierta-Retzius stipendiefond) and Uppsala University (Regnells Botaniska resestipendium) for studies on Southern Hemisphere lichenicolous fungi during his time at Uppsala University, and for field work, and grant travel support to Graz for 1994, when the major part of the study was undertaken. A travel grant from the Park Fund (NHM) permitted completion of the study. R       Bellemère, A. & Letrouit-Galinou, M.-A. (1987) Differentiation of lichen asci including dehiscence and sporogenesis: an ultrastructural study. Bibliotheca Lichenologica 25: 137–161. Coppins, B. J. (1989) Notes on the Arthoniaceae in the British Isles. Lichenologist 21: 195–216. Coppins, B. J. (1992) Arthonia Ach. (1806). In The Lichen Flora of Great Britain and Ireland (O. W. Purvis, B. J. Coppins, D. L. Hawksworth, P. W. James & D. M. Moore, eds.): 74–88. London: Natural History Museum Publications. Diederich, P. & Etayo, J. (1994) Taxonomic notes on the genus Plectocarpon (lichenicolous Ascomycotina). Nordic Journal of Botany 14: 589–600. Esslinger, T. L. & Egan, R. S. (1995) A sixth checklist of the lichen-forming, lichenicolous, and allied fungi of the continental United States and Canada. Bryologist 98: 467–549. Grube, M., Matzer, M. & Hafellner, J. (1995) A preliminary account of the lichenicolous Arthonia species with reddish, K+ reactive pigments. Lichenologist 27: 25–42. Hafellner, J. (1984) Studien in Richtung einer natürlicheren Gliederung der Sammelfamilien Lecanoraceae und Lecideaceae. Nova Hedwigia Beiheft 79: 241–371. Hafellner, J., Hertel, H., Rambold, G. & Timdal, E. (1993) A New Outline of the Lecanorales. Handout distributed at the First International Workshop on Ascomycete Systematics, available from the authors. Hepp, P. (1857) Die Flechten Europas in getrockneten mikroskopisch untersuchten Exemplaren mit Beschreibung und Abbildung ihrer Sporen. VII. Band. Heft 13 und 14. Nr. 354–403 und Beigabe Nr. 404–412. Zürich. Hitch, C. J. B. (1994) New, rare and interesting British lichen records. British Lichen Society Bulletin 75: 34–41. Holmgren, P. K., Holmgren, N. H. & Barnett, L. C. (1990) Index Herbariorum. Part 1: The herbaria of the world. Regnum Vegetabile 120: 1–693. Jørgensen, P. M. (1970) [‘ 1969 ’]) Sticta dufourii Del. and its parasymbiont Arthonia abelonae P. M. Jørg. n. sp. in Norway. Nova Hedwigia 18: 331–340. Kondratyuk, S. Y. & Galloway, D. J. (1994) Additional lichen records from New Zealand. 10. Australasian Lichenological Newsletter 34: 25–29. Kondratyuk, S. Y. & Galloway, D. J. (1995) Lichenicolous fungi and chemical patterns in Pseudocyphellaria. Bibliotheca Lichenologica 57: 327–345. Kondratyuk, S. Y., Galloway, D. J. & Hawksworth, D. L. (1994) Unguiculariopsis ahtii, and some other new lichenicolous fungi from Pseudocyphellaria. Acta Botanica Fennica 150: 93–97. Matzer, M. (1996) Lichenicolous ascomycetes with fissitunicate asci on foliicolous lichens. Mycological Papers 171: 1–202.

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Müller, J. [‘ Müller Argoviensis ’] (1887) Lichenologische Beiträge 26. Flora 70: 268–273, 283–288, 316–322, 336–338, 396–402, 423–429. Nylander, W. (1867) Addenda quaedam ad lichenographiam Novae Zelandiae. Flora 50: 438–440. Olivier, H. (1906) Le principaux parasites de nos lichens français. Bulletin de l’Academie Internationale de Géographie Botanique sér. 3, 16 (203): 187–200. Santesson, R. (1988) Fungi lichenicoli exsiccati. Fasc. 5–6. Thunbergia 6: 1–18. Schaerer, L. E. (1850) Enumeratio criticum lichenum Europaeorum quos ex nova methodus digerit. Bern. Triebel, D., Wedin, M. & Rambold, G. (1997) The genus Scutula (lichenicolous ascomycetes; Lecanorales): species growing on the Peltigera canina and P. horizontalis groups. Symbolae Botanicae Upsalienses, in press. Vobis, G. (1980) Bau und Entwicklung der Flechten-Pycnidien und ihrer Conidien. Bibliotheca Lichenologica 14: 1–141. Wedin, M. (1993) Arthonia pseudocyphellariae, a new lichenicolous fungus from the Southern Hemisphere. Lichenologist 25: 301–303. Wedin, M. (1994) New and noteworthy lichenicolous fungi from southernmost South America. Lichenologist 26: 301–310. Wedin, M. & Kondratyuk, S. (1997) Dactylospora plectocarpoides, a gall-forming species of Arthonia in Pseudocyphellaria. Lichenologist 29: 97–99 Accepted for publication 4 October 1997