Parmotrema robustum (Degel.) Hale (1974a: 338) MycoBank

Masson, Didier, Magain, Nicolas & Sérusiaux, Emmanuël, 2024, Small island but great diversity: thirty six species of Parmotrema (Parmeliaceae, lichenized Ascomycota), including sixteen new species, on Réunion (Mascarenes), with additional data from the Western Indian Ocean, Phytotaxa 657 (1), pp. 1-138 : 97-102

Parmotrema robustum (Degel.) Hale (1974a: 338) MycoBank no. 343120

Parmelia robusta Degel. (1941: 33) MycoBank no. 368777

Type:— FRANCE. Finistère: forêt du Cranou, 1898, C. Picquenard s.n. ( PC, n.v., lectotype designated by Hale 1965a; US [image!], isolectotype) .

( Fig. 37 )

Morphological description and chemistry based on molecularly analysed material from Réunion and mainland France (10 specimens, including topotype). Additional information from non-genetically analysed specimens is provided in square brackets.

Thallus foliose, loosely to moderately adnate, membranaceous to subcoriaceous, up to 16 × 13 cm [17 × 14 cm]. Lobes imbricate, rarely contiguous, irregularly branched, 5–20 mm wide, mostly concave when non-sorediate, frequently ascending and convolute when sorediate; margins undulated, smooth, crenate or laciniate, rarely lobulate, sometimes with black rim; apices rounded; eciliate to irregularly ciliate, rarely conspicuously ciliate ( Fig. 37C ). Cilia black, simple or irregularly branched, up to 3.5 mm [5 mm] long. Upper surface pale greenish grey to pale yellowish grey [pale greenish yellow], emaculate to ± punctiform white-maculate, most often faintly white-maculate, smooth near lobe tips but rugose and ± reticulated cracked in older parts, sorediate, lacking schizidia, pustules, dactyls, phyllidia and isidia; marginal rounded lobules occasionally present, up to 6 mm wide. Soralia at first marginal ± linear at the apex of laciniae of variable sizes (0.2–3 mm long) [sometimes the laciniae are indistinct, in such case the soralia are initially linear at the margins of the lobes], then ± labriform or subcapitate, finally ± coalescing and slightly spreading submarginally ( Fig. 37D ) [occasionally, sorediate laciniae develop into arbuscular structures, up to 4 mm long]; at times also laminal and subcapitate. Soredia granulose, (40)– 53.7 –(75) µm in diameter (n = 120, from 4 specimens, SD = 8.4 µm). Medulla white throughout. Lower surface smooth, granulate or verruculose in places, ± dull in the central part, brighter towards the periphery, black to the margin, or with a chestnut brown or buff marginal zone (ca. 1–10 mm wide), sometimes mottled or fully ivory at the tip of sorediate lobes. Rhizines concolor to the lower surface, in ± scattered groups, simple, rarely irregularly branched, up to 1 mm [2 mm] long. Apothecia not present [laminal, stipitate, up to 6 mm in diameter, disc non perforate, margin crenate and soon sorediate, from three fertile specimens from mainland France (no. 40.0973, 40.0979, 40.4179)]. [Ascospores (17)19.5– 24.4 –29.0(30) × 12.0– 14.3 –16.5(17) µm, n = 90, from the three specimens previously cited, mean values for each specimens: 25.4 × 14.4, 23.3 × 13.9, 24.5 × 14.6 µm; epispore 2– 3.0 –3.5 µm thick]. Pycnidia not present [found in specimen no. 29.2525, submarginal towards apices, black]. [ Conidia sublageniform 5–7 × ca. 1 µm].

Chemistry:— Spot tests and fluorescence: upper cortex K+ yellow, UV−; medulla K± slowly brownish, C−, KC + pinkish, P+ orange, UV−. Secondary metabolites ( TLC): upper cortex with atranorin and chloroatranorin [± usnic acid]; medulla with protocetraric acid (major), ± 1–3 unidentified fatty acids.

Geographical distribution:— Parmotrema robustum is classically considered to have a wide range, mainly tropical but also including some temperate areas ( Louwhoff 2009). However, remaining uncertainties in the delimitation of morphologically and chemically similar taxa (especially P. gardneri ) prevent a clear understanding of its distribution. For example, it is puzzling that only P. gardneri has been considered to occur in North America ( Brodo 2016, Esslinger 2021) as well as in East Africa ( Krog & Swinscow 1981, Swinscow & Krog 1988, Krog 2000), and not P. robustum . By contrast, only P. robustum has been reported from Europe, Macaronesia, North Africa and India ( Divakar & Upreti 2005, Hawksworth et al. 2008, Boutabia et al. 2015, Mishra & Upreti 2017).

In the islands of the western Indian Ocean, P. robustum is only known with certainty so far from Réunion ( des Abbayes 1961, as Parmelia dilatata ; van den Boom et al. 2011). On this island, this relatively common species is reported from 46 localities in 39 UTM 1× 1 km grid cells (or 33 UTM 2× 2 km grid cells, Fig. 37A ). These localities are distributed at elevations between 690 and 1980 m.

Ecology:—On Réunion, Parmotrema robustum is a mainly corticolous lichen; it has only been found once on rock. When corticolous, it grows on trunks as well as on branches. The phorophytes are various ( Acacia , Aphloia , Cryptomeria , Dombeya , Erica , Euodia , Hubertia , Melicope , Molinea , Monimia , Pandanus , Weinmannia , etc.) but a little more than half of the collections were made on tree heathers, especially Erica reunionensis . Leeward montane rainforest is the main habitat (48% of the localities), but P. robustum can also be found in Erica montane thicket (16%), windward montane rainforest (14%), Acacia montane forest (9%) or Pandanus submontane wet thicket (4.5%). Windward and leeward submontane rainforests, subalpine shrubland and degraded montane rainforest are less frequently reported habitats (2% each). The bioclimate of the localities is pluvial tropical; thermotype belts are mainly mesotropical = from upper thermotropical to upper mesotropical (330 ≤ It ≤ 543), ombrotype belts are variable = from lower humid to ultrahyperhumid (6.9 ≤ Io ≤ 26.7) ( Fig. 37B ).

Notes:—When Degelius (1941) introduced Parmelia robusta , he did not explicitly cite a type collection, but referred to Hue (1898) ‘syn. P. perlata Hue , verosim; non Lichen perlatus Huds.; descriptio ap. Hue in Journ. de Bot., 1898, p. 17–18’ [Note: the pagination quoted by Degelius (‘p. 17–18’) does not agree with the pagination in the Journal de Botanique (p. 242–244). It probably corresponds to the pagination of an offprint, since Hue’s description of Parmelia perlata occurs on the seventeenth, eighteenth and ninth pages of his article]. In Hue’s paper, two locations and two different substrates are reported on page 243 (= p. 18): ‘sur les rochers des monts d’Arès’ [= monts d’Arrée] and ‘sur les arbres dans la forêt de Crannou’ [= forêt du Cranou], and five other localities are listed on page 244. Thus, Hue cited more than one specimen, and none was indicated as a type. It seems that it was Hale (1965a: 245) who first designated a type: ‘Forêt de Crannou, Finistère, France, Picquenard in 1898 (P, holotype)’. Hale’s choice therefore corresponds to a lectotype rather than the holotype.

Protocetraric acid is a constant medullary secondary metabolite in Parmotrema robustum . The additional presence of unidentified fatty acids [up to three different ones in the material examined, up to five in a Bolivian specimen ( Kukwa et al. 2012)] is, however, highly variable in this species. Our ITS-based phylogenetic study shows that specimens with (no. 974.4708, 974.4751, 974.4826, 29.4170, 40.4176) and without (no. 974.3882, 974.3940, 974.4044, 974.4302) fatty acids are identical ( Fig. 4 , Table 3). In addition to atranorin and chloroatranorin, the upper cortex may contain usnic acid in variable amounts, to the point of giving it a greenish-yellow hue. This possible presence of usnic acid in the upper cortex of P. robustum , although reported by Sipman (2002), has remained largely unreported until now. Specimens without usnic acid were found on Réunion at 30 localities (mean elevation: 1447.7 m), while those containing it were found at 21 localities (mean elevation: 1495.5 m). Both chemotypes were collected together at five of these locations. In mainland France, we know one coastal locality (Finistère, Crozon, pointe de Dinan) with saxicolous P. robustum that also belong to both chemotypes. Thalli of both chemotypes can be found in the same square metre, or even closely intermingled. Apart from the colour of the upper surface, we did not find any morphological differences between these two types of thallus. It is unfortunate that we could only study sequences of specimens without usnic acid, despite several attempts to obtain molecular data for specimens containing usnic acid.

Although known for more than a century in Europe ( Hue 1898, Picquenard 1904, Hillmann 1939), the species now named Parmotrema robustum has remained poorly known, and the diagnostic characters to differentiate it from morphologically and chemically similar taxa are poorly defined. From our investigations, we can confirm that the development of marginal cilia, the type of soralia, the occurrence of usnic acid in the upper cortex and fatty acid(s) in the medulla are variable characters in this species. Regarding the development of marginal cilia, for example, the clade comprising our P. robustum whose ITS was studied ( Fig. 4 ) includes one specimen with no cilia at all, seven with cilia of varying abundance and length, ± unevenly distributed, and one with abundant long cilia. The existence of thalli of P. robustum with conspicuous cilia is the origin of the erroneous records of P. subarnoldii from France and Ireland ( des Abbayes 1961, Mitchell 1962). Of the taxa similar to P. robustum , P. gardneri is undoubtedly the most tricky to differentiate ( Kukwa et al. 2012, Egan et al. 2016). The morphologies of the two taxa appear almost identical, and both species share the same chemistry: atranorin, chloroatranorin, protocetraric acid and ± fatty acids (usnic acid, however, has not been reported in the upper cortex of P. gardneri to our knowledge). Two supposedly discriminating characters are generally used ( Krog & Swinscow 1981; Elix 1994; Louwhoff & Elix 1999, 2002; Sipman 2002; Galloway 2007; Egan et al. 2016): the consistency of the thallus (membranaceous in P. robustum , coriaceous in P. gardneri ) and the location of the soralia (mainly on marginal laciniae in P. robustum , mainly linear marginal or submarginal in P. gardneri ). We are rather sceptical about the discriminatory value of these two criteria. On one hand, because the more or less coriaceous character of a foliose thallus depends, at least partly, on the environmental conditions ( Krog & Swinscow 1981, Wang et al. 2018; first author’s observation). On the other hand, because the morphology of the soralia in P. robustum is very variable, as Tavares (1945) pointed out for Portuguese specimens and confirmed for our material from Réunion. According to the available information, it seems possible however to distinguish P. robustum from P. gardneri on the basis of ascospore size ( Table 12). The dimensions 18–22 × 8–10 µm that appear in several publications for each of the two species are probably taken from Krog & Swinscow (1981) for P. gardneri , and from Hale (1965a) for P. robustum . In his monograph, Hale placed Parmelia robusta , and some other taxa, in synonymy with Parmelia dilatata and gave for the latter species ascospore size of 18–22 × 8–10 µm (dimensions which, in fact, apparently do not correspond to either P. robustum or P. dilatatum ). For P. robustum , our data from collections from mainland France are consistent with those of des Abbayes (1934) from a specimen collected at the type locality (Cranou). The same applies to the measurements given by Dodge (1959) in the protologue of Parmelia gardneri and those published by Krog & Swinscow (1981). These results suggest that the ascospores of P. robustum are larger than those of P. gardneri . In this case, the measurements given by Louwhoff & Elix (1999) for P. gardneri would in fact correspond to a P. robustum .

The seven Reunionese specimens whose ITS was studied were clustered in the same well-supported monophyletic group, along with two specimens from mainland France (including a topotype), one from Portugal, and two from Canary Islands (both under the name P. dilatatum ; see entry for P. dilatatum ) ( Fig. 4 ). These seven specimens were collected in different localities scattered around the island ranging from 870 to 1925 m in elevation. In comparison, the only two P. gardneri whose ITS sequences are available in GenBank (accessions KP941029 and MK722215) form, together with one P. cristiferum, another well-supported clade ( Fig. 4 ). These three samples were all collected in Thailand. The results of this DNA-based approach tend to confirm that P. robustum and P. gardneri are two distinct species. However, the presence of a Thai specimen of P. cristiferum in the P. gardneri clade (already reported by DelPardo et al. 2019), and not in the Reunionese P. cristiferum clade, is puzzling. Parmotrema cristiferum and P. gardneri have quite similar morphologies, but the former species contains salazinic acid as a major substance while the latter contains protocetraric acid. Interestingly, some Kenyan specimens identified as P. gardneri were found to contain both salazinic and protocetraric acids in significant quantities ( Follmann & Schulz 1993). Clearly, more data, particularly molecular data, are needed to unravel this group. In the absence of any convincing evidence as to the presence of P. gardneri on Réunion, we therefore attribute all the specimens from this island examined to P. robustum .

In our 3-locus phylogenetic tree, P. robustum was part of a strongly supported clade that also includes P. dilatatum ( Fig. 3 ), both species being strongly supported as different by bPP and Stacey analyses ( Fig. 3 ).

Specimens examined:— FRANCE. Réunion: Bras-Panon, sentier de la Caroline, elev. 715 m, 21°01’35”S, 55°37’11”E, in windward submontane secondary rainforest with small Pandanus wet thickets, on bark of a branch of Pandanus montanus , 15 August 2017, D. Masson 974.4963 (LG); ibid., sentier de la Plaine des Lianes, elev. 690 m, 21°01’34”S, 55°36’45”E, in Pandanus submontane wet thicket, on bark of a branch of Pandanus montanus , 25 July 2005, D. Masson 974.1724 (Hb. DM); ibid., La Plaine des Lianes, Eden, along trail from the end of the road to kiosque, elev. 690 m, 21°01’39”S, 55°37’35”E, 01 October 1996, H. Krog RE31/15, RE31/16 & E. Timdal (O); Cilaos, Plateau des Chênes, on the GR R1 trail, elev. 1350 m, 21°07’31”S, 55°28’15”E, in secondary leeward montane rainforest, on bark of Erica reunionensis , 18 August 2015, D. Masson 974.4711 (Hb. DM); ibid., Ravine des Calumets, elev. 1310 m, 21°09’06”S, 55°29’39”E, in leeward montane rainforest, on ± mossy bark of a trunk of Aphloia theiformis , 21 August 2012, D. Masson 974.3940 (LG); ibid., elev. 1210 m, 21°09’18”S, 55°29’31”E, in secondary leeward montane rainforest, on bark of Erica reunionensis , 21 August 2012, D. Masson 974.3944 (Hb. DM); ibid., sentier du col du Taïbit, Plaine des Fraises, elev. 1925 m, 21°06’49”S, 55°26’17”E, in leeward montane rainforest, on bark at the base of an old Erica reunionensis trunk, 17 August 2015, D. Masson 974.4707 (Hb. DM), 974.4708 (LG); ibid., elev. 1930 m, 21°06’50”S, 55°26’21”E, in leeward montane rainforest, old Erica thicket, on bark of Erica reunionensis , 17 August 2015, D. Masson 974.4704 (Hb. DM); ibid., above Îlet des Salazes, elev. 1695 m, 21°06’48”S, 55°26’41”E, in secondary leeward montane rainforest with Pinus and Quercus plantations, on bark of a trunk of Quercus , 20 August 2012, D. Masson 974.3894 (Hb. DM); ibid., elev. 1730 m, 21°06’34”S, 55°26’46”E, in leeward montane rainforest, on bark of Erica reunionensis , 20 August 2012, D. Masson 974.3906 (REU), 974.3919 (Hb. DM); ibid., elev. 1740 m, 21°06’31”S, 55°26’48”E, in leeward montane rainforest, on bark of a trunk of Hypericum lanceolatum , 20 August 2012, D. Masson 974.3926 (Hb. DM); ibid., elev. 1775 m, 21°06’29”S, 55°26’54”E, rocky scree colonized by Erica reunionensis in leeward montane rainforest, on ± mossy basalt rock, 20 August 2012, D. Masson 974.3930 (Hb. DM); ibid., along road towards Bras Sec, at intersection with canyon of Bras de Benjoin, elev. 1360 m, 21°07’24”S, 55°28’53”E, 02 October 1996, H. Krog RE35/9, RE35/10 & E. Timdal (O); Entre-Deux, sentier de la Grande Jument , elev. 1115 m, 21°12’47”S, 55°28’58”E, in leeward montane rainforest, on bark of Erica reunionensis , 16 August 2015, D. Masson 974.4661 (Hb. DM); ibid., elev. 1130 m, 21°12’43”S, 55°28’59”E, in leeward montane rainforest, on bark of undetermined tree trunks, 16 August 2015, D. Masson 974.4670 (REU), 974.4671 (Hb. DM); La Plaine-des-Palmistes, Ligne Deux Mille en Dessous, elev. 870 m, 21°07’03”S, 55°39’06”E, in Pandanus submontane wet thicket, on bark of branches of Pandanus montanus , 23 August 2015 & 18 August 2017, D. Masson 974.4826 (LG), 974.4827 (REU), 974.4988, 974.5108 (Hb. DM); La Possession, la Grande Montagne , sentier des Lataniers, elev. 1330 m, 20°58’21”S, 55°23’31”E, in leeward montane rainforest, on bark of a branch of Pandanus , 19 August 2015, D. Masson 974.4726 (Hb. DM); ibid., elev. 1330 m, 20°58’17”S, 55°23’30”E, in leeward montane rainforest, on bark of the trunk of an undetermined shrub, 19 August 2015, D. Masson 974.4742 (Hb. DM); Piton Fougères, elev. 1420 m, 20°59’03”S, 55°24’07”E, in leeward montane rainforest, on bark of a trunk of Weinmannia , 04 August 2005, D. Masson 974.1941 (Hb. DM); ibid., Piton Marmite, elev. 1865 m, 21°03’28”S, 55°27’15”E, in Erica montane thicket, on ± mossy bark of Erica reunionensis , 23 August 2017, D. Masson 974.5101 (REU), 974.5102, 974.5103 (Hb. DM); ibid., elev. 1840 m, 21°03’32”S, 55°27’12”E, in Erica montane thicket, on bark of Erica reunionensis , 23 August 2017, D. Masson 974.5105 (Hb. DM); Le Tampon, Plaine des Cafres, sentier de Bébour, elev. 1600 m, 21°08’43”S, 55°34’14”E, in Erica montane thicket, on bark of Erica reunionensis and Hubertia tomentosa , 26 August 2012, D. Masson 974.4044 (LG), 974.4071 (Hb. DM); ibid., Plaine des Cafres, GR R2 trail, west of Piton Tortue, elev. 1740 m, 21°09’03”S, 55°32’43”E, in Erica montane thicket, on ± mossy bark of Erica reunionensis , 23 August 2013, D. Masson 974.4409 (REU), 974.4419 (Hb. DM); ibid., Plaine des Cafres, GR R2 trail, between Piton Tortue and Piton Lepervanche, elev. 1720 m, 21°09’11”S, 55°33’00”E, in Erica montane thicket, on ± mossy bark at the base of a trunk of Erica reunionensis , 23 August 2013, D. Masson 974.4404 (Hb. DM); ibid., Piton Desforges, elev. 1650 m, 21°11’46”S, 55°34’29”E, on bark of a trunk of Monimia , 30 September 1956, H. des Abbayes 29 (REN 000044); ibid., Piton Grand-Mère, elev. 1640 m, 21°10’45”S, 55°35’17”E, in Erica montane thicket, on bark of Erica reunionensis , 19 August 2017, D. Masson 974.5026 (REU), 974.5027–29 (Hb. DM); ibid., forêt de Notre-Dame de la Paix, botanical Trail, elev. 1700 m, 21°15’57”S, 55°36’07”E, in leeward montane rainforest, on bark of undetermined trees, 17 July 2005, D. Masson 974.1440 (REU), 974.1442 (Hb. DM); L’Étang-Salé, Chemin Canal, elev. 1075 m, 21°12’41”S, 55°22’36”E, in leeward submontane rainforest, on bark of a branch of Erica reunionensis , 27 August 2017, D. Masson 974.5142 (Hb. DM); Saint-Benoît, trail GR R1 from Gîte de Bélouve to Caverne Mussard, elev. 1980 m, 21°05.3’S, 55°31.3’E, rather well-lit area with mixed shrubs, including Erica sp. , on bark of Erica sp. , 02 June 2008, P. & B. van den Boom 40520 ( Hb. van den Boom); ibid., Piton de Bébour, elev. 1330 m, 21°07’45”S, 55°34’10”E, in windward montane rainforest, on bark of a trunk of Dombeya sp. , 07 April 2003, D. Masson 974.0033 (Hb. DM); ibid., Bébour, piste forestière de Takamaka, elev. 1360 m, 21°06’37”S, 55°33’57”E, in windward montane rainforest, on bark of a branch of Dombeya sp. , 16 August 2017, D. Masson 974.4969 (Hb. DM); Saint-Denis, sentier de la Roche Écrite, elev. 1420 m, 20°57’48”S, 55°26’24”E, in windward montane rainforest, on bark of a trunk of a young Erica reunionensis , 20 August 2015, D. Masson 974.4751 (LG); ibid., elev. 1515 m, 20°58’09”S, 55°26’26”E, in windward montane rainforest, on bark of a branch of an old Erica reunionensis , 20 August 2015, D. Masson 974.4759 (Hb. DM); ibid., Plaine d’Affouches, elev. 1720 m, 20°59’14”S, 55°26’02”E, in Acacia montane forest with Cyathea glauca and Nastus borbonicus , on bark of a branch of an old Erica reunionensis , 18 August 2012, D. Masson 974.3882 (LG), 974.3883 (Hb. DM); ibid., elev. 1480 m, 20°58’59”S, 55°24’35”E, in leeward montane rainforest, on bark of Erica sp. , 04 August 2005, D. Masson 974.1944 (Hb. DM); ibid., elev. 1490 m, 20°58’58”S, 55°24’51”E, in leeward montane rainforest, on bark of Erica sp. , 04 August 2005, D. Masson 974.1950 (Hb. DM); Saint-Joseph, sentier du Piton du Rond, elev. 1320 m, 21°18’07”S, 55°36’11”E, in leeward montane rainforest, on bark of a trunk of Melicope obscura , 18 August 2013, D. Masson 974.4302 (LG); ibid., elev. 1360 m, 21°17’55”S, 55°36’19”E, in leeward montane rainforest, on bark of a trunk of Pandanus montanus , 18 August 2013, D. Masson 974.4304 (Hb. DM); ibid., Piton du Rond, elev. 1375 m, 21°17’55”S, 55°36’23”E, in leeward montane rainforest, on bark of a trunk of Molinea alternifolia , 18 August 2013, D. Masson 974.4305 (Hb. DM); ibid., Grand Coude, elev. 1375 m, 21°16’32”S, 55°37’48”E, in secondary windward montane rainforest, on bark of Cryptomeria japonica , 24 August 2017, D. Masson 974.5114 (Hb. DM); Saint-Paul, ravine La Source, elev. 1700 m, 21°04’39”S, 55°21’36”E, in Acacia montane forest, on bark of Acacia heterophylla , 02 August 2005, D. Masson 974.1922 (Hb. DM); ibid., Le Maïdo, along the road to the viewpoint, elev. 1950 m, 21°03’42”S, 55°22’43”E, Acacia heterophylla forest, 05 October 1996, H. Krog RE44/6 & E. Timdal (O); Saint-Pierre, forêt du Haut de Mont Vert, Camp Mussard, elev. 1600 m, 21°16’52”S, 55°36’12”E, in leeward montane rainforest, on bark of a branch of Dombeya sp. , 17 August 2017, D. Masson 974.4977 (Hb. DM); Salazie, Piton d’Enchain, elev. 1350 m, 21°02’37”S, 55°29’53”E, in windward montane rainforest, on bark of Melicope borbonica , 13 April 2003, D. Masson 974.0311 (Hb. DM); ibid., Bélouve, elev. 1690 m, 21°04’34”S, 55°31’46”E, in Erica montane thicket, on bark of branches of Erica reunionensis , 25 August 2013, D. Masson 974.4458 (REU), 974.4459 (Hb. DM); ibid., forêt de Bélouve, track from Gîte de Bélouve to viewpoint, elev. 1500 m, 21°03’39”S, 55°32’10”E, 30 September 1996, H. Krog RE25/29 & E. Timdal (O); ibid., forêt de Bélouve, near Gîte de Bélouve, elev. 1520 m, area with mature Acacia heterophylla trees in mixed forest along road and path, on Acacia heterophylla , 27 May 2008, P. & B. van den Boom 39783 ( Hb. van den Boom).

Selected specimens studied for comparison:— FRANCE. Finistère: Crozon, pointe de Dinan, elev. 35 m, 48°14’13”N, 4°33’57”W, low maritime heath on rocky headland, on ± mossy quartzite rocks, 23 August 2007, D. Masson 29.2518, 29.2519, 29.2521–25 (Hb. DM); Hanvec, forêt du Cranou, elev. 110 m, 48°18’59”N, 4°06’03”W, in oak-beech forest with bilberry, on mossy bark of Quercus petraea , 21 August 2007, D. Masson 29.2490 (topotype, Hb. DM); Le Faou, forêt du Cranou, east of the Manoir forest house, elev. 130 m, 48°18’58”N, 4°06’25”W, in Atlantic beech forest, on bark of Quercus , 23 December 2012, J.-Y. Monnat 29.4170 (topotype, LG); Plougastel, rochers de quartzite entre le bourg et le pont, exposition N, 31 March 1933, des Abbayes s.n. (REN 000054). Landes: Ondres, Yrieu, elev. 20 m, 43°34’22”N, 1°25’33”W, in an old pine plantation with Prunus laurocerasus undergrowth, on bark of a trunk of a dead Pinus pinaster , 28 December 2012, D. Masson 40.4176 (LG); ibid., elev. 15 m, 43°34’19”N, 1°25’30”W, at the edge of a small pond, on bark of a trunk of Salix atrocinerea , 28 December 2012, D. Masson 40.4179 (Hb. DM); Soustons, Piquère, elev. 10 m, 43°46’26”N, 1°19’46”W, in an alder wood at the western edge of Étang de Soustons, on bark of a trunk of Alnus glutinosa , 24 February 2004, D. Masson 40.0979 (Hb. DM); ibid., Tuquéou, elev. 10 m, 43°46’21”N, 1°20’20”W, in a pine forest with Quercus suber and Ilex aquifolium , on ± mossy bark of a trunk of Pinus pinaster , 24 February 2004, D. Masson 40.0973 (Hb. DM).

SPAIN. Canary Islands: La Gomera, Alrededores del monte de El Cedro, 560 m, sobre la corteza, 04 August 2009, A. Crespo & A. Santos 6i, 6h (MAF-Lich 20689, 20698) .

Figures

FIGURE 3. Phylogeny of the Parmotrema species studied. Best ML tree resulted from a RaxML analysis of three loci (EF1-α, ITS, mtSSU) and 102 specimens. Punctelia toxodes was selected as the outgroup. Bootstrap values are represented above the branches, and thick branches have bootstrap support value ≥ 70. Results of the species delimitation analyses are summarized to the right of the terminal labels of the tree. The first column corresponds to the results of the Stacey analysis, while the second column corresponds to the results of the bPP analysis. Specimens attributed the same colour were reconstructed as part of the same putative species by the species delimitation analysis. Major medullary extrolites are also shown for each specimen.

FIGURE 4. Global tree (best scoring maximum likelihood tree) of Parmotrema based on the fungal ITS barcoding marker. Figure can be enlarged for a better reading of labels. Accessions in black are those retrieved from GenBank on June 2023. Those in red are those produced by the authors for this study. Bootstrap support is indicated on branch when ≥ 70%.

FIGURE 37. Parmotrema robustum. A: Distribution on Réunion (UTM 2×2 km grid system); B: Bioclimatic characteristics of collection sites (abbreviations and threshold values for thermotype and ombrotype horizons from Rivas-Martínez et al. 2011: 17–18); C: Gross morphology of thallus (Masson 974. 4044); D: Sorediate lobes with young soralia ± labriform or subcapitate at the apex of laciniae, then ± coalescing and slightly spreading submarginally with age (Masson 974.4826). Scale bars:A = 10 km; C = 10 mm; D = 4 mm