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Rhizocarpon timdalii, a new lichen species from north-west Europe and north-east North America
Lichenologist 34(2): 95-100 (2002) doi:10.1006/lich.2002.0379, available online at http://www.idealibrary.com on
Rhizocarpon timdalii, a new lichen species from north-west Europe and north-east North America Per G. IHLEN and Alan M. FRYDAY Abstract: The new species Rhizocarpon timdalii, is described from north-west Europe and north-east North America. The ecology and distribution of the new species are also discussed. © 2002 Published by Elsevier Science Ltd on behalf of The British Lichen Society
Introduction While studying the taxonomy of the nonyellow species of Rhizocarpon DC. with hyaline and muriform ascospores in the Nordic countries (Ihlen in prep.) and in North America (Fryday in prep.) we, independently, discovered a taxon with a combination of characters that did not agree with any species in recent treatments of the genus Rhizocarpon (e.g. Feuerer 1978; Timdal & Holtan-Hartwig 1988; Purvis et al. 1992; Fryday 2000). This species, which is characterized by a brown thallus, containing an unidentified fatty acid or lacking lichen products, small and more or less convex apothecia and areoles, a dark blue-green epihymenium, and distinctly eumuriform, hyaline ascospores, is described here as Rhizocarpon timdalii.
Materials and Methods About 3100 Nordic specimens, from the herbaria AMNH, BG, C, DUKE, H, LD, O, S, TRH, TROM, and UPS were screened by the first author for the new species. In addition, the second author discovered ten
Per G. Ihlen: Department of Botany, University of Bergen, Allegaten 41, N-5007 Bergen, Norway. Alan M. Fryday: Herbarium, Department of Plant Biology, Michigan State University, East Lansing, MI 48824, USA. 0024-2829/02/020095 + 06 $35.00/0
collections among c. 200 specimens sent to him for identification from NE North America and one from his own, extensive collections from the British Isles. Thallus and apothecial characters were examined by light microscopy on hand-cut sections. Height of the hymenium (including the epihymenium) and the photobiont layer and the diameter of the photobiont cells were measured in water; other measurements were made in 10% KOH. The nomenclature of the insoluble pigments of the ascomata follows the system proposed by Meyer & Printzen (2000). It should be noted that, due to subjective colour impressions, we are not fully convinced that the pigment of the epihymenium of the new species represents Cinereorufa-green, or whether an undescribed pigment is involved. A total of 19 specimens were examined by thin-layer chromatography (TLC) according to the method described by Culberson & Kristinsson (1970), with later modifications. In Rhizocarpon species there is a strong amyloid reaction in the hymenial gel, making observation of the ascus tholus difficult when using standard techniques with the sections pretreated with KOH. To overcome this problem, hand cut sections of apothecia were mounted in water on a glass slide. After most of the water was soaked up, a drop of 50% solution of commercial bleach (C) was added, and was absorbed immediately. Finally, the sections were washed with water and a drop of a 002-003% iodine solution was added. The estimated values of the quantitative characters have been given as: in.-)(x - SD)-(x+SD)(-max.) where min. and max. are the extreme values, x the arithmetic sample mean, and SD the corresponding standard deviation of the sample. Twelve specimens were selected to estimate each quantitative character, and from these a total of 48 measurements were made, except for the range of the thickness of the photobiont
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FIG. 1. Rhizocarpon timdalii, thallus and apothecia (part of holotype). Scale =1 mm.
tinge, (4-) 7-13 (-21) areoles per mm2, corticate; medulla I — , crystals absent. Hypothallus distinct, black. Photobiont chlorococcoid; photobiont layer continuous, 80-200 |a.m thick; photobiont cells green, Taxonomy ± rounded, 7-0-18-0 |xm diam. Rhizocarpon timdalii Ihlen & Fryday Apothecia (Fig. 1) irregularly arranged, sp. nov. rounded, black, (0-3-) 0-4-0-5 (-0-6) mm Thallus brunneus, areolae convexae. Apothecia diam.; disc initially flat, distinctly convex convexa, (0-3—) 0-4-0-5 (-0-6) mm diametro. Epihy- when mature; proper margin (0-02-) 0-03menium obscure aeruginosum. Ascosporae eumurifor- 0-07 (-0-08) mm thick, at first distinct, mae hyalinae, (23-0-) 33-5-42-5 (-48-0) x (13-0-) becoming indistinct or absent when the disc 15-0-20-0 (-23-0) urn. Thallus sine acida vel acidum is convex and mature, concolorous with the pingue indeterminatum continens. Typus: USA. Minnesota, Cook County, Sawbill disc. Exciple in section dark blue-green, Lake near campground, 23 miles N of Tofte, near shore K —, N+ purple, HC1+ blue (Cinereorufain mixed conifer hardwood forest, Sec. 7, T62N, R4W green) or reddish brown in water, at least in [47°53'N 90°52'W], 28 June 1974, C. M. Wetmore lower part, K ± intensifying or K+ purple, 22228 (MIN—holotypus; BG—isotypus). intensifying N ± intensifying, HC1 ± (Atra-red); crystals absent. Hypothecium (Figs 1-3) brown in water, K — or K+ darker, N — or Thallus (Fig. 1) areolate; areoles ± convex, N and HC1 ± intensifying (Arnoldianarounded, brown, sometimes with a greyish brown). Hymenium hyaline, (100-) 126-191
layer and the size of the photobiont cells, for which ten measurements were made on each. All measurements were made on mature structures.
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FIG. 2. Rhizocarpon timdalii., ascospores. Scale= 16 |jm.
(-250) um high; epihymenium mostly dark blue-green, K —, N+ purple, HC1+ blue (Cinereorufa-green), frequently with small, brownish patches, crystals absent. Hamathecialfilamentsbranched and anastomosing, (1 -6-) 2-2-3-3 (-4-0) um thick, with swollen apices when pigmented, (3-2-) 3-9-5-8 (-6-5) um thick. Asci 8-spored, 1+ slightly blue; tholus apex with a small I + dark blue cap. Ascospores (Fig. 2) ± ellipsoid, hyaline, (23-0-) 33-5-42-5 (-48-0) x (13-0-) 15-020-0 (-23-0) um, length/breadth-ratio (1-8-) 2-0-2-5 (-2-7), eumuriform, with a total of (13-) 16-24 (-29) cells in optical view. Conidiomata not seen.
habitats are open Quercus (oak) forest, coastal coniferous forest, open old-growth Betula alleghaniensis (yellow birch) forest, open pine forests, and pine plantation; several specimens, including the type, have been collected close to lakes or the coast. In North America, associated taxa include Acarospora sp., Lecanora polytropa, Lepraria caesioalba, L. neglecta s. lat., Melanelia sorediata, Porpidia tuberculosa, Rhizocarpon geographicum, R. reductum, R. rubescens, Stereocaulon nanodes, and Umbilicaria polyphylla. In the Nordic countries, associated taxa include Ephebe lanata, Lecanora polytropa, Lepraria neglecta s. lat., Lepraria sp., Rhizocarpon badioatrum, R. geographicum, R. Chemistry. Thallus K - , C - , P d - , I - . lecanorinum, R. reductum, Umbilicaria deusta, An unidentified fatty acid with Rf-classes and Umbilicaria sp. A 5, B 5-6, C 5-6 (nine specimens, including the holotype), or lichen products not Distribution. Rhizocarpon timdalii is known detected by TLC (ten specimens, including from north-west Europe, where it has the isotype). The unidentified fatty acid been found in the U. K. (Wales), Norway, occurred in both European and North Sweden, and Finland, and from north-east American specimens. North America (Connecticut, Maine, Massachusetts, Michigan, Minnesota, and Etymology. The new species is named in New York). In Europe, it has been collected honour of Dr Einar Timdal, University of up to an elevation of 200 m in Fennoscandia Oslo, for his contributions to the taxonomy (Norway, Akershus), and to 650 m in Wales of Rhizocarpon. (Caernarvonshire). In the USA, it has been collected at altitudes up to c. 520 m Ecology. Rhizocarpon timdalii grows on (Connecticut, Canaan mountain). acid rocks and, in Europe, has been found Additional specimens examined. Norway: Akershus: mostly on exposed and wet rocks, often near lakes. In addition, one specimen was col- Enebakk, Bortervann, Tangetjemet, 200 m, 1989, & Timdal 7212 (O); NW shore of lake lected on rock with a high metal content. Holtan-Hartwig Tangetjemet, 200 m, 1987, Timdal 4947 (O); AurskogOne specimen was recorded on a heath and Holand, 1 km E of S0ndre Mangen, 195 m, 1987, two in a wood. In the USA, the recorded Timdal4956 (O).—Sweden: Smdland: Gamleby, 1947,
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FIG. 3. Distribution of Rhizocarpon timdalii.
Magnusson 21558a (UPS). Bohuslan: Stenungsund, Barrens off Gadway Road, 04 miles S of Cannon Stenungson, 1954, Magnusson 24247 (LD and UPS); Corners, 1996, E. Lay 96-0600 (hb. Lay). Norum, Stenungson, 1953, Magnusson 23892 (UPS); Udevalla, c. 1 km NE of Cederslund, 70 m, 2001, Ihlen 1033 (BG). Vastergotland: Goteborg, Anggrdsbergen, Discussion 1930, Magnusson 12182 (UPS); Landvetter, near lake Groen, 1910, Magnusson 7598a (UPS); Lerum, Rhizocarpon timdalii is very similar to R. Stenskullen, 1934, Magnusson 14213 (UPS). Sodermanland: Trosa, 1925, Malme (S). Varmland: Hammaro, reductum Th. Fr., a name resurrected for the 15 km S of Karlstad, Store Holmen, by Lake Vanern, species previously referred to as R. obscura100 m, 1985, Owe-Larsson 3118 (UPS).—Finland: tum (Ach.) A. Massal. The basionym of R. Varsinais-Suomi: Turku, Mukurimaki, 1922, Vainio obscuratum, Lecidea petraea var. obscuratum, (H). Great Britain: Wales: VC 48, Caernarvonshire, has been shown to be based on a mixed type Snowdonia, Clogwyn y Garnedd, 23/613544, alt. 650 m, 1996, A. Fryday (E).—USA: Connecticut: (Fryday 2000) and to be a synonym of Iitchfield Co., Canaan, SE part of Canaan mountain, Fuscidea lygaea (P. G. Ihlen, unpublished). alt. 518-527 m, 1991, E. Lay 91-0346 (FH). Maine: In fact, most of the older specimens of R. Washington Co., Great Wass Island Preserve, 1993, E. timdalii had been identified as R. obscuratum. Lay 93-0497 (hb. Lay). Massachusetts: Worcester Co., Princeton, Wachusett Mountain State Reservation, alt. However, the new species can be readily 426-480 m, slope between entrance gate and Down separated from R. reductum by the distinctly Summit Road, 1998, P. May 4190 (FH). Michigan: blue-green colour (Cinereorufa-green) of Keweenaw Co. Isle Royal NP, south side, of Maskey the epihymenium, the small and convex Bay, c. 0-4 miles north of Wallace Lake, 1991, D. Ladd areoles, and the longer and broader asco15544 (MSC). Minnesota: St. Louis Co., Voyages NP., E side of Bowman Bay, on south side of Kabetogama spores with, usually, more cells per Lake, 1978, C. M. Wetmore 31820 (MIN); W side of ascospore. Rhizocarpon reductum has a Browns Bay (Sand Point Lake area), 1979, C. M. brownish epihymenium (Atra-brown), often Wetmore 39951 (MIN); Cook Co., Susie Islands, near with a greenish tinge (Cinereorufa-green), Grand Portage, 1980, C. M. Wetmore 42035 (MIN); Lake Co., Jack Pine Mountain, 18 miles SE of Ely Sec more or less flat areoles, and ascospores 35, 1977, C. M. Wetmore 27417 (MIN). New York: measuring (22-0-) 25-5-34-0 (-40-0) x Clinton Co., Mooers, Gadway Sandstone Pavement (10-0-) 12-0-15-5 (-18-0) um, and with a
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total of (6-) 8-13 (-17) cells per ascospore |xm, respectively (the sizes of the ascospores in optical view (numbers are based on are based on material from the Nordic material from the Nordic countries). In countries). Furthermore, R. distinctum and addition, R. reductum contains stictic acid, R. subpostumum have a K+ purple exciple whereas R. timdalii contains either an un- (Atra-red) and, in addition, R. distinctum has identified fatty acid or lichen products are an 1+ blue medulla. absent. Due to the irregular production Rhizocarpon timdalii is a north temperate of the unidentified fatty acid, it is probably of to hemiboreal species of damp areas in open little taxonomic importance. lowland forests. In Europe, it has not been Anatomically, R. timdalii most closely recorded further north than southernmost resembles R. sublavatum Fryday, with which Finland, and in North America it has yet to it shares the relatively small apothecia, rela- be recorded from Canada. The highest tively large eumuriform ascospores, and known elevation is 650 m, and this was at its blue-green epihymenium (Cinereorufa- most southerly locality in Europe (Wales). green). However, the two species are readily Our studies of the non-yellow Rhizocarpon distinguished by thallus morphology, that of species have led us to examine many hunR. sublavatum being flat, cracked-areolate, dreds of collections from northern Europe whereas that of R. timdalii consists of and North America and we have not strongly convex areoles. The apothecia of R. encountered any specimens of R. timdalii sublavatum also remain flat with a persist- from outside the areas indicated in Fig. 3. ently raised margin, whereas those of R. While it remains possible that R. timdalii is timdalii become convex and immarginate on more widely distributed, based on the maturity. The apothecial characters of R. present material, the species appears to show sublavatum are also shared by R. anaperum an amphi-atlantic distribution. Ahti (1977), (Vain.) Vain., which, in addition, has a assigns this distribution to only a small brown, granular thallus and a brown epihy- group of lichen species (e.g. Cladonia strepmenium. Rhizocarpon timdalii may also key silis (Ach.) Grognot, Erioderma pedicellatum out (e.g. Fryday 2000) as R. lavatum (Fr.) (Hue) P. M. Jorg., Lasallia pustulata (L.) Hazsl., but that species has much larger Merat, Pycnotheliapapillaria (Ehrh.) Dufour, apothecia with a thick tumid margin, a and Stereocaulon dactylophyllum Florke) smoother thallus, and less strongly muriform whereas Dahl (1998) states that the lichen ascospores. It is interesting to note that these and bryophyte floras of Newfoundland two species, together with R. amphibium and western Northern Europe are very (Fr.) Th. Fr. (also with hyaline and muri- similar and considers the region on either form ascospores), are all found in moist side of the North Atlantic to form a floristic habitats (Fryday 2000; Gilbert & Giavarani region. Rhizocarpon timdalii appears to be 2000). Rhizocarpon amphibium is readily primarily a species of open deciduous separated from R. timdalii as it does not have forests, and in this respect it differs a thallus composed of convex areoles and from the species mentioned by Ahti (1977), also has a reddish brown epihymenium re- which occur in the boreal coniferous acting K+ purple (Atra-red). For differences forests. between R. sublavatum and R. anaperum, see Fryday (2000). Rhizocarpon distinctum Th. We thank Beate Helle Ingvartsen (Bergen) for technical Fr., R. postumum (Nyl.) Arnold, and R. assistance, Ralph Common (East Lansing) for his helpsubpostumum Arnold may also superficially ful suggestion on elucidating the ascus-structure of resemble R. timdalii, but these species have Rhizocarpon timdalii, and Douglas Ladd (St Louis), Lay (Boston), Phillip May (Boston), and the submuriform, smaller ascospores measuring Elisabeth curators of AMNH, BG, C, DUKE, H, LD, MIN, O, (22-0-) 24-0-32-5 (-40) x (10-0-) 12-0- S, TRH, TROM, and UPS for making their Rhizocar15-5 (-18) |am, (15-0-) 17-1-24-3 (-28-0) x pon collections available to us. Mr P. May also made (8-0-) 9-2-10-3 (-13-0) um, and (15-0-) some very helpful comments on the manuscript and 18-2-23-1 (-25-0) x (7-0-) 9-3-12-7 (-13-0) Prof. Per M. Jorgensen (Bergen) kindly corrected the Latin diagnosis.
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Gilbert, O. & Giavarini, V. (2000) The lichen vegetation of lake margins in Britain. Lichenologist 32: Ahti, T. (1977) Lichens of the boreal coniferous zone. 365-386. In Lichen Ecology (M. R. D. Seaward, ed.): 145— Meyer, B. & Printzen, C. (2000) Proposal for a stand181. London: Academic Press. ardized nomenclature and characterization of inDahl, E. (1998) The Phytogeography of Northern Europe. soluble lichen pigments. Lichenologist 32: 571-583. Cambridge: Cambridge University Press. doi:10.1006/lich.2000.0294. Culberson, C. F. & Kristinssson, H. (1970) A stand- Purvis, O. W., James, P. W., Holtan-Hartwig, J., ardized method for the identification of lichen Timdal, E. & Clayden, S. C. (1992) Rhizocarpon products. Journal of Chromatography 46: 85-93. Lam. ex DC. (1805). In The Lichen Flora of Great Feuerer, T. (1978) Zur Kenntnis der Flechtengattung Britain and Ireland (O. W. Purvis, B. J. Coppins, Rhizocarpon in Bayern. Berichte der Bayerischen D. L. Hawksworth, P. W. James & D. M. Moore, Botanischen Gesellschaft 49: 59-135. eds): 531-542. London: Natural History Museum Publications. Fryday, A. (2000) On Rhizocarpon obscuratum (Ach.) Massal., with notes on some related species in Timdal, E. & Holtan-Hartwig, J. (1988) A preliminary the British Isles. Lichenologist 32: 207-224. key to Rhizocarpon in Scandinavia. Graphis Scripta doi: 10.1006/lich.2000.0269. 2: 41-54. REFERENCES
Accepted for publication 28 January 2002
Rhizocarpon timdalii, a new lichen species from north-west Europe and north-east North America Per G. IHLEN and Alan M. FRYDAY Abstract: The new species Rhizocarpon timdalii, is described from north-west Europe and north-east North America. The ecology and distribution of the new species are also discussed. © 2002 Published by Elsevier Science Ltd on behalf of The British Lichen Society
Introduction While studying the taxonomy of the nonyellow species of Rhizocarpon DC. with hyaline and muriform ascospores in the Nordic countries (Ihlen in prep.) and in North America (Fryday in prep.) we, independently, discovered a taxon with a combination of characters that did not agree with any species in recent treatments of the genus Rhizocarpon (e.g. Feuerer 1978; Timdal & Holtan-Hartwig 1988; Purvis et al. 1992; Fryday 2000). This species, which is characterized by a brown thallus, containing an unidentified fatty acid or lacking lichen products, small and more or less convex apothecia and areoles, a dark blue-green epihymenium, and distinctly eumuriform, hyaline ascospores, is described here as Rhizocarpon timdalii.
Materials and Methods About 3100 Nordic specimens, from the herbaria AMNH, BG, C, DUKE, H, LD, O, S, TRH, TROM, and UPS were screened by the first author for the new species. In addition, the second author discovered ten
Per G. Ihlen: Department of Botany, University of Bergen, Allegaten 41, N-5007 Bergen, Norway. Alan M. Fryday: Herbarium, Department of Plant Biology, Michigan State University, East Lansing, MI 48824, USA. 0024-2829/02/020095 + 06 $35.00/0
collections among c. 200 specimens sent to him for identification from NE North America and one from his own, extensive collections from the British Isles. Thallus and apothecial characters were examined by light microscopy on hand-cut sections. Height of the hymenium (including the epihymenium) and the photobiont layer and the diameter of the photobiont cells were measured in water; other measurements were made in 10% KOH. The nomenclature of the insoluble pigments of the ascomata follows the system proposed by Meyer & Printzen (2000). It should be noted that, due to subjective colour impressions, we are not fully convinced that the pigment of the epihymenium of the new species represents Cinereorufa-green, or whether an undescribed pigment is involved. A total of 19 specimens were examined by thin-layer chromatography (TLC) according to the method described by Culberson & Kristinsson (1970), with later modifications. In Rhizocarpon species there is a strong amyloid reaction in the hymenial gel, making observation of the ascus tholus difficult when using standard techniques with the sections pretreated with KOH. To overcome this problem, hand cut sections of apothecia were mounted in water on a glass slide. After most of the water was soaked up, a drop of 50% solution of commercial bleach (C) was added, and was absorbed immediately. Finally, the sections were washed with water and a drop of a 002-003% iodine solution was added. The estimated values of the quantitative characters have been given as: in.-)(x - SD)-(x+SD)(-max.) where min. and max. are the extreme values, x the arithmetic sample mean, and SD the corresponding standard deviation of the sample. Twelve specimens were selected to estimate each quantitative character, and from these a total of 48 measurements were made, except for the range of the thickness of the photobiont
© 2002 Published by Elsevier Science Ltd on behalf of The British Lichen Society
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FIG. 1. Rhizocarpon timdalii, thallus and apothecia (part of holotype). Scale =1 mm.
tinge, (4-) 7-13 (-21) areoles per mm2, corticate; medulla I — , crystals absent. Hypothallus distinct, black. Photobiont chlorococcoid; photobiont layer continuous, 80-200 |a.m thick; photobiont cells green, Taxonomy ± rounded, 7-0-18-0 |xm diam. Rhizocarpon timdalii Ihlen & Fryday Apothecia (Fig. 1) irregularly arranged, sp. nov. rounded, black, (0-3-) 0-4-0-5 (-0-6) mm Thallus brunneus, areolae convexae. Apothecia diam.; disc initially flat, distinctly convex convexa, (0-3—) 0-4-0-5 (-0-6) mm diametro. Epihy- when mature; proper margin (0-02-) 0-03menium obscure aeruginosum. Ascosporae eumurifor- 0-07 (-0-08) mm thick, at first distinct, mae hyalinae, (23-0-) 33-5-42-5 (-48-0) x (13-0-) becoming indistinct or absent when the disc 15-0-20-0 (-23-0) urn. Thallus sine acida vel acidum is convex and mature, concolorous with the pingue indeterminatum continens. Typus: USA. Minnesota, Cook County, Sawbill disc. Exciple in section dark blue-green, Lake near campground, 23 miles N of Tofte, near shore K —, N+ purple, HC1+ blue (Cinereorufain mixed conifer hardwood forest, Sec. 7, T62N, R4W green) or reddish brown in water, at least in [47°53'N 90°52'W], 28 June 1974, C. M. Wetmore lower part, K ± intensifying or K+ purple, 22228 (MIN—holotypus; BG—isotypus). intensifying N ± intensifying, HC1 ± (Atra-red); crystals absent. Hypothecium (Figs 1-3) brown in water, K — or K+ darker, N — or Thallus (Fig. 1) areolate; areoles ± convex, N and HC1 ± intensifying (Arnoldianarounded, brown, sometimes with a greyish brown). Hymenium hyaline, (100-) 126-191
layer and the size of the photobiont cells, for which ten measurements were made on each. All measurements were made on mature structures.
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FIG. 2. Rhizocarpon timdalii., ascospores. Scale= 16 |jm.
(-250) um high; epihymenium mostly dark blue-green, K —, N+ purple, HC1+ blue (Cinereorufa-green), frequently with small, brownish patches, crystals absent. Hamathecialfilamentsbranched and anastomosing, (1 -6-) 2-2-3-3 (-4-0) um thick, with swollen apices when pigmented, (3-2-) 3-9-5-8 (-6-5) um thick. Asci 8-spored, 1+ slightly blue; tholus apex with a small I + dark blue cap. Ascospores (Fig. 2) ± ellipsoid, hyaline, (23-0-) 33-5-42-5 (-48-0) x (13-0-) 15-020-0 (-23-0) um, length/breadth-ratio (1-8-) 2-0-2-5 (-2-7), eumuriform, with a total of (13-) 16-24 (-29) cells in optical view. Conidiomata not seen.
habitats are open Quercus (oak) forest, coastal coniferous forest, open old-growth Betula alleghaniensis (yellow birch) forest, open pine forests, and pine plantation; several specimens, including the type, have been collected close to lakes or the coast. In North America, associated taxa include Acarospora sp., Lecanora polytropa, Lepraria caesioalba, L. neglecta s. lat., Melanelia sorediata, Porpidia tuberculosa, Rhizocarpon geographicum, R. reductum, R. rubescens, Stereocaulon nanodes, and Umbilicaria polyphylla. In the Nordic countries, associated taxa include Ephebe lanata, Lecanora polytropa, Lepraria neglecta s. lat., Lepraria sp., Rhizocarpon badioatrum, R. geographicum, R. Chemistry. Thallus K - , C - , P d - , I - . lecanorinum, R. reductum, Umbilicaria deusta, An unidentified fatty acid with Rf-classes and Umbilicaria sp. A 5, B 5-6, C 5-6 (nine specimens, including the holotype), or lichen products not Distribution. Rhizocarpon timdalii is known detected by TLC (ten specimens, including from north-west Europe, where it has the isotype). The unidentified fatty acid been found in the U. K. (Wales), Norway, occurred in both European and North Sweden, and Finland, and from north-east American specimens. North America (Connecticut, Maine, Massachusetts, Michigan, Minnesota, and Etymology. The new species is named in New York). In Europe, it has been collected honour of Dr Einar Timdal, University of up to an elevation of 200 m in Fennoscandia Oslo, for his contributions to the taxonomy (Norway, Akershus), and to 650 m in Wales of Rhizocarpon. (Caernarvonshire). In the USA, it has been collected at altitudes up to c. 520 m Ecology. Rhizocarpon timdalii grows on (Connecticut, Canaan mountain). acid rocks and, in Europe, has been found Additional specimens examined. Norway: Akershus: mostly on exposed and wet rocks, often near lakes. In addition, one specimen was col- Enebakk, Bortervann, Tangetjemet, 200 m, 1989, & Timdal 7212 (O); NW shore of lake lected on rock with a high metal content. Holtan-Hartwig Tangetjemet, 200 m, 1987, Timdal 4947 (O); AurskogOne specimen was recorded on a heath and Holand, 1 km E of S0ndre Mangen, 195 m, 1987, two in a wood. In the USA, the recorded Timdal4956 (O).—Sweden: Smdland: Gamleby, 1947,
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FIG. 3. Distribution of Rhizocarpon timdalii.
Magnusson 21558a (UPS). Bohuslan: Stenungsund, Barrens off Gadway Road, 04 miles S of Cannon Stenungson, 1954, Magnusson 24247 (LD and UPS); Corners, 1996, E. Lay 96-0600 (hb. Lay). Norum, Stenungson, 1953, Magnusson 23892 (UPS); Udevalla, c. 1 km NE of Cederslund, 70 m, 2001, Ihlen 1033 (BG). Vastergotland: Goteborg, Anggrdsbergen, Discussion 1930, Magnusson 12182 (UPS); Landvetter, near lake Groen, 1910, Magnusson 7598a (UPS); Lerum, Rhizocarpon timdalii is very similar to R. Stenskullen, 1934, Magnusson 14213 (UPS). Sodermanland: Trosa, 1925, Malme (S). Varmland: Hammaro, reductum Th. Fr., a name resurrected for the 15 km S of Karlstad, Store Holmen, by Lake Vanern, species previously referred to as R. obscura100 m, 1985, Owe-Larsson 3118 (UPS).—Finland: tum (Ach.) A. Massal. The basionym of R. Varsinais-Suomi: Turku, Mukurimaki, 1922, Vainio obscuratum, Lecidea petraea var. obscuratum, (H). Great Britain: Wales: VC 48, Caernarvonshire, has been shown to be based on a mixed type Snowdonia, Clogwyn y Garnedd, 23/613544, alt. 650 m, 1996, A. Fryday (E).—USA: Connecticut: (Fryday 2000) and to be a synonym of Iitchfield Co., Canaan, SE part of Canaan mountain, Fuscidea lygaea (P. G. Ihlen, unpublished). alt. 518-527 m, 1991, E. Lay 91-0346 (FH). Maine: In fact, most of the older specimens of R. Washington Co., Great Wass Island Preserve, 1993, E. timdalii had been identified as R. obscuratum. Lay 93-0497 (hb. Lay). Massachusetts: Worcester Co., Princeton, Wachusett Mountain State Reservation, alt. However, the new species can be readily 426-480 m, slope between entrance gate and Down separated from R. reductum by the distinctly Summit Road, 1998, P. May 4190 (FH). Michigan: blue-green colour (Cinereorufa-green) of Keweenaw Co. Isle Royal NP, south side, of Maskey the epihymenium, the small and convex Bay, c. 0-4 miles north of Wallace Lake, 1991, D. Ladd areoles, and the longer and broader asco15544 (MSC). Minnesota: St. Louis Co., Voyages NP., E side of Bowman Bay, on south side of Kabetogama spores with, usually, more cells per Lake, 1978, C. M. Wetmore 31820 (MIN); W side of ascospore. Rhizocarpon reductum has a Browns Bay (Sand Point Lake area), 1979, C. M. brownish epihymenium (Atra-brown), often Wetmore 39951 (MIN); Cook Co., Susie Islands, near with a greenish tinge (Cinereorufa-green), Grand Portage, 1980, C. M. Wetmore 42035 (MIN); Lake Co., Jack Pine Mountain, 18 miles SE of Ely Sec more or less flat areoles, and ascospores 35, 1977, C. M. Wetmore 27417 (MIN). New York: measuring (22-0-) 25-5-34-0 (-40-0) x Clinton Co., Mooers, Gadway Sandstone Pavement (10-0-) 12-0-15-5 (-18-0) um, and with a
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total of (6-) 8-13 (-17) cells per ascospore |xm, respectively (the sizes of the ascospores in optical view (numbers are based on are based on material from the Nordic material from the Nordic countries). In countries). Furthermore, R. distinctum and addition, R. reductum contains stictic acid, R. subpostumum have a K+ purple exciple whereas R. timdalii contains either an un- (Atra-red) and, in addition, R. distinctum has identified fatty acid or lichen products are an 1+ blue medulla. absent. Due to the irregular production Rhizocarpon timdalii is a north temperate of the unidentified fatty acid, it is probably of to hemiboreal species of damp areas in open little taxonomic importance. lowland forests. In Europe, it has not been Anatomically, R. timdalii most closely recorded further north than southernmost resembles R. sublavatum Fryday, with which Finland, and in North America it has yet to it shares the relatively small apothecia, rela- be recorded from Canada. The highest tively large eumuriform ascospores, and known elevation is 650 m, and this was at its blue-green epihymenium (Cinereorufa- most southerly locality in Europe (Wales). green). However, the two species are readily Our studies of the non-yellow Rhizocarpon distinguished by thallus morphology, that of species have led us to examine many hunR. sublavatum being flat, cracked-areolate, dreds of collections from northern Europe whereas that of R. timdalii consists of and North America and we have not strongly convex areoles. The apothecia of R. encountered any specimens of R. timdalii sublavatum also remain flat with a persist- from outside the areas indicated in Fig. 3. ently raised margin, whereas those of R. While it remains possible that R. timdalii is timdalii become convex and immarginate on more widely distributed, based on the maturity. The apothecial characters of R. present material, the species appears to show sublavatum are also shared by R. anaperum an amphi-atlantic distribution. Ahti (1977), (Vain.) Vain., which, in addition, has a assigns this distribution to only a small brown, granular thallus and a brown epihy- group of lichen species (e.g. Cladonia strepmenium. Rhizocarpon timdalii may also key silis (Ach.) Grognot, Erioderma pedicellatum out (e.g. Fryday 2000) as R. lavatum (Fr.) (Hue) P. M. Jorg., Lasallia pustulata (L.) Hazsl., but that species has much larger Merat, Pycnotheliapapillaria (Ehrh.) Dufour, apothecia with a thick tumid margin, a and Stereocaulon dactylophyllum Florke) smoother thallus, and less strongly muriform whereas Dahl (1998) states that the lichen ascospores. It is interesting to note that these and bryophyte floras of Newfoundland two species, together with R. amphibium and western Northern Europe are very (Fr.) Th. Fr. (also with hyaline and muri- similar and considers the region on either form ascospores), are all found in moist side of the North Atlantic to form a floristic habitats (Fryday 2000; Gilbert & Giavarani region. Rhizocarpon timdalii appears to be 2000). Rhizocarpon amphibium is readily primarily a species of open deciduous separated from R. timdalii as it does not have forests, and in this respect it differs a thallus composed of convex areoles and from the species mentioned by Ahti (1977), also has a reddish brown epihymenium re- which occur in the boreal coniferous acting K+ purple (Atra-red). For differences forests. between R. sublavatum and R. anaperum, see Fryday (2000). Rhizocarpon distinctum Th. We thank Beate Helle Ingvartsen (Bergen) for technical Fr., R. postumum (Nyl.) Arnold, and R. assistance, Ralph Common (East Lansing) for his helpsubpostumum Arnold may also superficially ful suggestion on elucidating the ascus-structure of resemble R. timdalii, but these species have Rhizocarpon timdalii, and Douglas Ladd (St Louis), Lay (Boston), Phillip May (Boston), and the submuriform, smaller ascospores measuring Elisabeth curators of AMNH, BG, C, DUKE, H, LD, MIN, O, (22-0-) 24-0-32-5 (-40) x (10-0-) 12-0- S, TRH, TROM, and UPS for making their Rhizocar15-5 (-18) |am, (15-0-) 17-1-24-3 (-28-0) x pon collections available to us. Mr P. May also made (8-0-) 9-2-10-3 (-13-0) um, and (15-0-) some very helpful comments on the manuscript and 18-2-23-1 (-25-0) x (7-0-) 9-3-12-7 (-13-0) Prof. Per M. Jorgensen (Bergen) kindly corrected the Latin diagnosis.
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Gilbert, O. & Giavarini, V. (2000) The lichen vegetation of lake margins in Britain. Lichenologist 32: Ahti, T. (1977) Lichens of the boreal coniferous zone. 365-386. In Lichen Ecology (M. R. D. Seaward, ed.): 145— Meyer, B. & Printzen, C. (2000) Proposal for a stand181. London: Academic Press. ardized nomenclature and characterization of inDahl, E. (1998) The Phytogeography of Northern Europe. soluble lichen pigments. Lichenologist 32: 571-583. Cambridge: Cambridge University Press. doi:10.1006/lich.2000.0294. Culberson, C. F. & Kristinssson, H. (1970) A stand- Purvis, O. W., James, P. W., Holtan-Hartwig, J., ardized method for the identification of lichen Timdal, E. & Clayden, S. C. (1992) Rhizocarpon products. Journal of Chromatography 46: 85-93. Lam. ex DC. (1805). In The Lichen Flora of Great Feuerer, T. (1978) Zur Kenntnis der Flechtengattung Britain and Ireland (O. W. Purvis, B. J. Coppins, Rhizocarpon in Bayern. Berichte der Bayerischen D. L. Hawksworth, P. W. James & D. M. Moore, Botanischen Gesellschaft 49: 59-135. eds): 531-542. London: Natural History Museum Publications. Fryday, A. (2000) On Rhizocarpon obscuratum (Ach.) Massal., with notes on some related species in Timdal, E. & Holtan-Hartwig, J. (1988) A preliminary the British Isles. Lichenologist 32: 207-224. key to Rhizocarpon in Scandinavia. Graphis Scripta doi: 10.1006/lich.2000.0269. 2: 41-54. REFERENCES
Accepted for publication 28 January 2002