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Dimelaena oreina (Ach.) Norman (1852: 231) MycoBank no. 384375 Lecanora straminea var. oreina Acharius (1810: 432). Type:— SWITZERLAND. ‘In alpibus Helvetiae’, Schleicher, 1018A (H-ACH, lectotype!). For further synonyms see Sheard & Ahti (1975). (Fig. 4) Thallus crustose, thick or thin, loosely attached to the substrate, areolate at center and radiate-plicate at margin, areolae large, up to 2.00 mm long, 1.15 mm wide, irregular in shape, usually darkened around the areolae and surface margin; marginal lobes narrow, Apothecia cryptolecanorine to lecanorine, innate to adnate, often touching each other, roundish, 0.18–1.20 mm in diam., disc black, disc margin concolorous with thallus; epihymenium brown; hymenium hyaline, 80–100 μm high, inspersed with oil droplets; hypothecium hyaline, 80–125 μm high; asci clavate, Bacidia - type, 8-spored; ascospores brown, 1-septate, thin walled, 8.5–13 × 4.5–7 μm, markedly constricted at septum when mature. Pycnidia numerous, immersed; conidia bacilliform, 3–6 × 0.7–1 μm. Chemistry: Usnic and gyrophoric acids, occasionally with stictic acid in our examined specimens from China. Ecology and distribution: This species usually grows on exposed siliceous rock, at elevations of 2798–3942 m. Distributed in North America, South America (rare), Europe, Asia and South Africa (rare) (Sheard & Ahti 1975, Mayrhofer et al. 1996). Notes: Dimelaena oreina is the type species of Dimelaena. One specimen from Switzerland (where D. oreina was originally described) has a newly generated molecular profile to confirm the phylogenetic position of the genus Dimelaena. Specimens of D. oreina from China cluster with those from Europe in the phylogenetic tree. Furthermore, the specimens in this clade contain gyrophoric acid, which is consistent with spot test results from the type specimen (K–; KC–). The species still needs further study by molecular and chemical analysis including all the five chemotypes from Europe. Additional specimens examined. CHINA. Gansu Province: Subei Co., Nanshan Mt., near 29th Mengke Glacier, 3942 m, 39°12′42.51″N, 95°23′00.50″E, 23 May 2018, Wang Lisong et al. 18-59460; Subei Co., Nanshan Mt., near 29th Mengke Glacier, 3909 m, 39°12′43.08″N, 95°22′59.77″E, 23 May 2018, Wang Lisong et al. 18-59432; Subei Co., Nanshan Mt., near 29th Mengke Glacier, 3942 m, 39°12′43.93″N, 95°23′00.32″E, 23 May 2018, Wang Lisong et al. 18-59450; Subei Co., Nanshan Mt., near 29th Mengke Glacier, 3885 m, 39°12′40.74″N, 95°23′03.95″E, 23 May 2018, Wang Lisong et al. 18-58504; Sunan Co., on the route from Sunan to Qilian, 3492 m, 38°39′16.51″N, 99°29′29.16″E, 30 May 2018, Wang Lisong et al. 18-58843; Yumen Ci., Yuerhong Vil., 3332 m, 39°38′13.77″N, 97°09′15.57″E, 27 May 2018, Wang Lisong et al. 18-58641; Yumen Ci., Yuerhong Vil., 3291 m, 39°38′14.84″N, 97°09′15.94″E, 27 May 2018, Wang Lisong et al. 18-59552. Qinghai Province: Huangyuan Co., rocky slope beside G315, 2798 m, 36°46′53.65″N, 101°07′21.77″E, 18 May 2018, Wang Lisong et al. 18-58134., Published as part of Ai, Min, Zhong, Qiuyi, Scheidegger, Christoph, Wang, Lisong & Wang, Xinyu, 2022, Revision of Dimelaena Norman (Caliciaceae, Ascomycota) species containing usnic acid reveals a new species and a new combination from China, pp. 259-272 in Phytotaxa 574 (4) on pages 266-268, DOI: 10.11646/phytotaxa.574.4.1, http://zenodo.org/record/7389058, {"references":["Norman, J. M. (1852) Conatus praemissus redactionis novae generum nonnullorum lichenum in organis fructificationis vel sporis fundatae. Nytt Magazin Naturvidenskapene 7: 213 - 252.","Acharius, E. (1810) Lichenographia Universalis. Gottingae, Apud Iust. Frid. Danckwerts. 689 pp.","Sheard, J. W. & Ahti, T. (1975) The lichen Dimelaena oreina in east-central Asia, with notes on its typification and chemical races. Annales Botanici Fennici 12: 89 - 92.","Mayrhofer, H., Matzer, M., Wippel, A. & Elix, J. A. (1996) The genus Dimelaena (lichenized Ascomycetes, Physciaceae) in the southern hemisphere. Mycotaxon 58: 293 - 311."]}

Glaciers being very sensitive to climate change have been identified as one of the best indicators of climate change and evidences have proved that most of the Himalayan glaciers have receded with an increased rate during the recent past under the influence of global warming. Lichenometric study was carried out on the moraines of Milam glacier (located in Pithoragarh district of Uttarakhand) with the help of lichen species Dimelaena oreina having an average annual growth rate of 1.31 mm. The study revealed that Milam glacier has receded 1450 m in last 69.37 years with an average recession rate of 20.90 m/year. Since lichenometric studies are cost effective and ecofriendly in comparison to carbon dating, satellite and remote sensing based studies and also reliable, hence, it should be promoted in Himalaya which is an abode of glaciers.

Ten foliose and placodioid species of Physciaceae are reported from the National Park Torres del Paine and from other areas in southernmost Chile. Phaeophyscia constipate and Physconia perisidiosa are reported as new to the Southern Hemisphere, Phaeophyscia endococcina var. endococcina and Phaeorrhiza nimbosa as new to South America, and Dimelaena oreina and Physcia kalbii as new to Chile. The latter was recorded only from the island of Chiloé. Dimelaena appears to be rare in Magallanes and has been recorded only from one steppe locality. Phaeophyscia constipate and Phaeorrhiza nimbosa appear to be confined to the driest steppes, in areas with occurrences of rock outcrops associated with calcareous soil. Physconia muscigena has a similar habitat ecology, but a wider distribution, and is quite common. Physconia perisidiosa and Physcia adscendens were found to be very common in all bioclimatic zones surveyed in the lowland of Torres del Paine. The Physciaceae species treated here are all bipolar or subcosmopolitan, and belong to genera lacking an austral or South American element in the area studied, in contrast to the pattern in all other reasonably large macrolichen groups, except among cetrarioid genera. Their habitat ecology is also very similar to conditions known in the Northern Hemisphere. On the other hand, other widely distributed Northern Hemisphere species such as Physcia stellaris and P. aipolia have known distribution patterns in South America which are disjunct and northern and very different from those of the species treated here.

Four chemotypes of Dimelaena oreina are reported from the analysis of 140 specimens from the Iberian Peninsula. Chemotypes II (usnic and gyrophoric acids) and V (usnic and stictic acids) were previously known from this area, but chemotype I (usnic and fumarprotocetraric acids) is new to the region, and chemotype VII (usnic, stictic, and gyrophoric acids) is new for the species. Chemical and phytogeographical evidence suggests that chemotypes V and VII are closely related. In addition to geographic distributions, phytogeographic affinities and minor morphological trends, some lichens and lichenicolous fungi growing on Dimelaena oreina chemotypes are reported. Among all the species of Dimelaena hitherto known (e.g., Mayrhofer et al. 1996; Sheard 1974; Sheard & Mayrhofer 1984), Dimelaena oreina (Ach.) Norman is well characterized by its yellowgreen thallus containing usnic acid in the cortex, lecanorine apothecia, and an hyaline hypothecium. It is widespread in Temperate and Boreal regions of the northern hemisphere and is also known in the southern hemisphere (Mayrhofer et al. 1996). In Europe, its distribution is from Scandinavia to the Mediterranean. Dimelaena oreina is one of the best studied lichens from a chemical point of view. It is chemically variable, with six chemotypes recognized worldwide (Culberson et al. 1984; Leuckert & Poelt 1978; Leuckert et al. 1975, 1981, 1987; Mayrhofer et al. 1996; Sheard 1974, 1977; Sheard & Ahti 1975). According to the terminology of Sheard (1974, 1977) and Culberson et al. (1984), each chemotype is designated with a number, and is characterized by the content of the main substances (see Table 1). Except for the chemotype with sphaerophorin, described from California (Culberson et al. 1984) all chemotypes occur in Europe. They are distributed following a north to south gradient, with northern Europe having fewer and less complex chemotypes than southern territories (Leuckert & Poelt 1978). Chemotype III is predominant in northern Scandinavia, chemotype I is the most frequent in some mountainous regions of central Europe (with chemotype IV often associated), and chemotype V becomes the predominant chemotype in other parts of central Europe and in the Mediterranean region. A good correlation between chemistry and elevation has been also demonstrated in a study from South Tyrol (Leuckert et al. 1981). Chemotype V dominated at lower elevations, whereas at higher elevations chemotype I was the most frequent. The overall distribution of the chemotypes is summarized in Table 1. The main aim of this paper is to study the chemical variability of D. oreina in the Iberian Peninsula (Andorra, Portugal and Spain), a particularly interesting territory considering its great climatic and biological diversity, as well as the above mentioned chemical richness and complexity in southern Europe. In the Iberian Peninsula, D. oreina is a widespread lichen, extending from regions close to the coast to the highest mountains, mostly associated with hard siliceous rocks. Sporadic analysis of Spanish and Portuguese specimens by Leuckert et al. (1975), Sheard (1977), and Culberson et al. (1984) reported two chemotypes (II and V) for this territory. A rare occurrence of chemotype III (Sheard 1977) in Spain is here excluded, and needs confirmation because of the low elevation and typical Mediterranean character of the locality. Also, a few samples from the Canary Islands and Morocco have been analyzed; this complementary information is included in "representative specimens studied." MATERIALS AND METHODS The study is based on material kept at BCC, LEB, LISU, MA, MAF, VAB, and Etayo priv. herb. The main morphological and anatomical characters were studied by means of standard light microscopic techniques. A total of 142 samples, 140 from the Iberian Peninsula, one from the Canary Islands and one from Morocco, were analyzed by Thin-Layer Chromatography (TLC) and 12 selected specimens by High-Performance Liquid Chromatography 0007-2745199139-44$O.7510 This content downloaded from 157.55.39.129 on Thu, 28 Jul 2016 04:05:12 UTC All use subject to http://about.jstor.org/terms 40 THE BRYOLOGIST [VOL. 102 TABLE 1. Lichen substances content and distribution of the chemotypes of Dimelaena oreina, excluding rare occurrences FU = fumarprotocetraric acid, GY = gyrophoric acid, ST = stictic acid and SPH = sphaerophorin. Usnic acid present in all the chemotypes. Greenland Eastern Western Southern ChemoRussia FennoscanCentral Southern and North North Hemitype Substances and Asia dia Europe Europe N. Canada America America sphere

A new chemotype of Dimelaena oreina from California produces sphaerophorin as the major constituent and gyrophoric acid as an accessory of variable concentration. Chemical structures are proposed for two new orcinol-type para-depsides also detected in this chemotype. Isosphaeric acid is an isomer of sphaerophorin with a n-C7H,,-side chain on the A-ring and a one-carbon side chain on the B-ring. Superlatolic acid has the full reduced seven-carbon side chain on both rings. Fuscidea viridis, a new species described here from Norway and Sweden, produces all possible 4-O-methylated orcinol para-depsides with phenolic units having n-C5H11- and n-C7H5,- side chains. In addition to the major product, perlatolic acid, and a trace of superlatolic acid, two new depsides-hyperlatolic acid and

World distribution of the species of Dimelaena and Thamnolia, and chemical variants, are considered in relation to current concepts of conti- nental drift. It is concluded that both genera date from the Permian-Triassic and paleogeographies of species and chemotypes are presented which are consistent with the established sequence of continental movements. In addition, long- distance dispersal has probably occurred in both species of Thamnolia. Seven chemotypes of Dimelaena oreina are now known and are interpreted as belonging to three races with differing paleogeographies. The races correspond to the fumarprotocetraric acid, gyrophoric/acid deficient chemotypes and the stictic/ norstictic chemotypes. They have not been given taxonomic recognition, how- ever, because the acid deficient chemotype may not be genetically homogenous, possibly incorporating acid deficient phases of the two other races in addition to the acid deficient phase of the gyrophoric acid chemotype. The fumarprotocetra- ric and gyrophoric acid chemotype incorporates substances of two races and does not occur outside the area of sympatry. This chemotype is best regarded as either a cross or a mycobiont chimera of its constituent races. Little attention has been paid to phytogeography of lichens relative to other groups of macroscopic organisms. There are two reasons for this. Firstly, few lichen genera are sufficiently well known taxonomically for worldwide distribution to be adequately documented and, secondly, the apparent widespread distribution of some taxa has lead to a belief that their phytogeography is inherently uninteresting. The cosmopolitan dis- tribution of such lichens may be a function of either their abilities for long-distance dis- persal or of their great age and passive dispersal by movements of the earth's crust. While plate tectonics provides an explanation for the present distribution of many groups of organisms, to the knowledge of this author, only W. L. Culberson (1972) considered the phytogeography of the lichens in this light. The two small genera Dimelaena Norm. and Thamnolia Ach. ex Schaer. are well known and have widespread distributions. These provide an opportunity for further examining the role of continental drift in lichen phytogeography. The species of Dime

The taxonomy, chemistry, and distribution of the species of Dimelaena Norm. in North America are summarized and the relationship of the genus to others in the Buelliaceae discussed. Four species are reported: D. californica (Magn.) Sheard, comb. nov., D. oreina (Ach.) Norm., D. radiata (Tuck.) Hale & W. Culb., and D. thysanota (Tuck.) Hale & W. Culb. A new chemical strain of D. oreina has been discovered in the western mountains. It is characterised by the presence of stictic and norstictic acids and is allopatric with the eastern, fumarprotocetraric acid strain. Two species are excluded from the genus Dimelaena. These are Rinodina angelica Stizenb. and R. chrysomelaena (Ach.) Tuck. Two other new combinations, D. diffractella (Miill. Arg.) Sheard and Lecanora (sect. Aspicilia) stellata (Lynge) Sheard, are made for species from South America and Greenland, respectively. The genus Dimelaena is distinguished from Rinodina primarily by its radiate-plicate thallus margin. Until recently it has, however, been considered to be a part of the genus Rinodina in North American (Tuckerman, 1882; Fink, 1935; Hale & Culberson, 1966) and most other treatments (Zahlbruckner, 1926; Magnusson, 1951). This paper results from my larger study of the genus Rinodina in North America which indicates that the current tendency to treat Dimelaena as a separate genus (Poelt, 1969; Hale & Culberson, 1970) is correct. Unfortunately, the delimitation of Dimelaena by Hale and Culberson is in error and perpetuates the confusion in the earlier literature regarding the taxonomy of this group. Since the publication of Zahlbruckner's treatise (1926), it has generally been assumed that Dimelaena (syn. Rinodina sect. Placothallia) is a homogeneous entity. Hale and Culberson (1970) appear to have followed Zahlbruckner (1931) in defining the limits of the genus, although it is not clear why Rinodina nimbosa was excluded. (Perhaps because Lamb and Henssen (1968) had already shown that R. nimbosa is not closely related to Dimelaena oreina and its relatives.) Poelt (1969) also recognized that Rinodina sect. Placothallia is heterogeneous and formalized this fact by treating Rinodina oreina as a member of Dimelaena but retaining Rinodina balanina, R. nimbosa, and two other less well known species in the genus Rinodina, despite the fact that these species all have lobate margins to their thalli. 1I thank the curators who loaned material from the following herbaria-BM, COLO, DUKE, FH, G, MICH, MIN, NY, SCS, UAC, UC, UPS, US, wis-and Drs. J. W. Thomson and C. M. Wetmore for the loan of material from their personal herbaria. Mr. J. Waddington prepared the figures. Part of this work was carried out while I held a National Research Council of Canada Postdoctoral Fellowship and subsequent funding has been by operating grants from N.R.C.C. 2 Department of Biology, University of Saskatchewan, Saskatoon. This content downloaded from 157.55.39.153 on Mon, 19 Sep 2016 05:10:55 UTC All use subject to http://about.jstor.org/terms 1974] SHEARD: DIMELAENA OF NORTH AMERICA 129 The genus has its North American, and possibly world, centre of distribution in southern California. Two monographic treatments of the lichens of this region have been made-by Herre (1910) and Hasse (1913) respectively-and are therefore of particular interest, the latter pointing to some critical taxonomic problems. LIMITS OF THE GENUS DIMELAENA Rinodina sect. Placothallia as understood by Zahlbruckner (1926) can now be shown to contain at least three groups of species. 1) Species which belong to the genus Dimelaena, characterised by a radiate-plicate thallus margin and by an unthickened spore wall. The apothecia in the genus are generally lecanorine but D. californica, some forms of D. oreina, and D. radiata lack a raised margin, which may be indicative of a cryptolecanorine origin (Dughi, 1952; Sheard, 1967). Two species also have a brown hypothecium, and together these characters provide reasons for suspecting an evolutionary relationship with Melanaspicilia (Vainio, 1909). Lamb and Henssen (1968) undertook an extensive ontogenetic study of the apothecia of this group and showed that it was more closely related to Buellia than Rinodina, where it had been placed by Dodge and Baker (1938). Sheard (1967) had earlier arrived at the same conclusion on morphological and anatomical grounds. In this connection it should be noted that the apothecia of the southern hemisphere species, Dimelaena diffractella, become distinctly lecideine as they age. The significance of these findings in the present context is that the evolutionary origins of Dimelaena should probably be sought in Buellia rather than in Rinodina. 2) Species pertaining to Rinodina sect. Eurinodina which have spores with thickened walls, characteristically unequally thickened (polarilocular), lecanorine apothecia, and lacking radiate-plicate thalline margins. This necessitates the transfer of Dinmelaena angelica and D. chrysomelaena. 3) Species which have polarilocular spores, lecanorine apothecia, and squamulose or radiate-plicate thalline margins. This group needs further study as it may or may not be heterogeneous, depending on the true affinities of such species as Rinodina nimbosa and R. balanina from the European arctic. Lamb and Henssen (1968) relate the latter to Dimelaena (syn. Rinodina sect. Placothallia) despite the fact that Vainio (1909) described it as having unequally thickened spore walls. The former authors note, quite correctly, that if this group is to be maintained as a taxon distinct from sect. Eurinodina, then a new epithet will be necessary, the name Placothallia being inapplicable as its type species, Rinodina oreina, is also the type of Dimelaena.