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 Author Masson, Didier 0000-0002-3340-5472 Vertevoye, 2860 route d’Irieu, F- 40390 Saint-Martin-de-Seignanx, France di. masson @ wanadoo. fr; https: // orcid. org / 0000 - 0002 - 3340 - 5472 di.masson@wanadoo.fr Author Magain, Nicolas 0000-0001-5409-9518 Evolution and Conservation Biology, InBios research centre, Sart Tilman B 22, Quartier Vallée 1, Chemin de la vallée 4, B- 4000 Liège, Belgium nicolas. magain @ uliege. be; https: // orcid. org / 0000 - 0001 - 5409 - 9518 nicolas.magain@uliege.be Author Sérusiaux, Emmanuël 0000-0002-3340-5472 Vertevoye, 2860 route d’Irieu, F- 40390 Saint-Martin-de-Seignanx, France di. masson @ wanadoo. fr; https: // orcid. org / 0000 - 0002 - 3340 - 5472 & Evolution and Conservation Biology, InBios research centre, Sart Tilman B 22, Quartier Vallée 1, Chemin de la vallée 4, B- 4000 Liège, Belgium e. serusiaux @ uliege. be; https: // orcid. org / 0000 - 0002 - 0456 - 0131 * Corresponding author & Vertevoye, 2860 route d’Irieu, F- 40390 Saint-Martin-de-Seignanx, France di. masson @ wanadoo. fr; https: // orcid. org / 0000 - 0002 - 3340 - 5472 di.masson@wanadoo.fr text Phytotaxa 2024 2024-06-27 657 1 1 138 http://dx.doi.org/10.11646/phytotaxa.657.1.1 journal article 10.11646/phytotaxa.657.1.1 1179-3163 13217474 Parmotrema tinctorum (Despr. ex Nyl.) Hale (1974a: 339) MycoBank no. 343140 Parmelia tinctorum Despr. ex Nyl. (1872: 547) MycoBank no. 542088 Type :— SPAIN . Canary Islands , s.d., J.M. Despréaux (?) s.n. (H-NYL 35365, n.v ., holotype ; fide Krog & Swinscow 1981 ) . ( Fig. 41 ) Thallus foliose, moderately adnate, membranaceous to coriaceous, up to 15 × 18 cm . Lobes irregular, generally broadly rounded, contiguous to imbricate, 5–20 mm wide; margins ± sinuate, entire, crenate or dentate, eciliate ( Fig. 41C ). Upper surface pale greenish grey to pale yellowish grey, ± shiny, duller towards centre, emaculate to faintly white-maculate, smooth to rugose, occasionally ± cracked in older parts, isidiate, lacking schizidia, pustules, dactyls, soralia. Isidia sparse to dense, at times partly obscuring the thallus surface, marginal and laminal; ± globose to cylindrical, simple to coralloid-branched, apices concolor or brownish, eciliate ( Fig. 41D ), 0.05–0.14 mm in diameter, up to 2.5 mm high; sometimes granular and ± sorediate; in old, ± decaying parts, some isidia early flattened and give rise to phyllidia or lobules. Lobules occasional, mostly marginal, also laminal in old parts, up to 10 × 13 mm . Medulla white throughout. Lower surface smooth or rugulose, ± shiny, duller towards centre, black to the margin, or with a chestnut brown erhizinate marginal zone (ca. 4–15 mm wide) at main lobe tips, lateral isidiate lobes occasionally with an ivory-white erhizinate marginal zone (up to 3.5 mm wide). Rhizines in ± scattered clusters, concolor to the lower surface, simple or fasciculate, often short and fairly coarse, occasionally slender and up to 2.5 mm long. Apothecia very rare (fertile thalli found in two localities out of 53), laminal, shortly stipitate, up to 6 mm in diameter, disc perforate, margin ± crenate, isidiate; amphithecium maculate, isidiate. Ascospores absent. Pycnidia quite frequent, submarginal towards the lobe apices, occasionally also on isidia, black. Conidia filiform, 8–13(16) × ca. 1 µm. FIGURE 41. Parmotrema tinctorum . A : Distribution on Réunion (UTM 2×2 km grid system), lemon-yellow cells = specimens examined, pale yellow cells with a cross = specimens not examined; B : Bioclimatic characteristics of collection sites (abbreviations and threshold values for thermotype and ombrotype horizons from Rivas-Martínez et al . 2011: 17–18 ); C : Part of thallus showing the eciliate lobe margins ( Masson 974.5078 ); D : Isidiate lobe with coralloid-branched and eciliate isidia ( Masson 974.4767 ). Scale bars: A = 10 km; C = 10 mm; D = 2 mm. Chemistry :— Spot tests and fluorescence : upper cortex K+ yellow, UV−; medulla K−, C + and KC + red, P−, UV−. Secondary metabolites ( TLC ): upper cortex with atranorin and chloroatranorin; medulla with lecanoric acid (major), ± undetermined substance ( UV + golden yellow; pale yellowish with sulphuric acid and heating; Rf classes: A4-5, C 5; minor/trace) Geographical distribution :—Widespread pantropical species that extends into some subtropical and temperate areas to about the 40 th parallels ( Chen et al . 2005 , GBIF 2023a ). In the MIOI hotspot, it has been reported from Madagascar ( Hue 1899 , des Abbayes 1961 , Hale 1965 a , Aptroot 1990), Seychelles ( Seaward & Aptroot 2003 , 2006 , 2009 ; Diederich et al . 2017 ), Mauritius ( David & Hawksworth 1995 , Diederich & Ertz 2020) and Réunion ( Hue 1899 , van den Boom et al . 2011). On the latter island, Parmotrema tinctorum has been collected since the end of the 19 th century ( Hue 1899 ), and it is currently one of the most frequently recorded species of Parmotrema ( Fig. 5 ). It was found to occur in at least 58 localities, distributed in 54 UTM 1× 1 km grid cells (or 46 UTM 2× 2 km grid cells, Fig. 41A ), and located mainly in the Piton des Neiges massif and in the oldest parts of the Piton de la Fournaise massif between 10 and 1845 m elevation. The species is newly reported from the island of Rodrigues, in the Mascarenes. Ecology :—Of the 62 samples from Réunion examined, 53 were found on bark, nine on volcanic rock. When corticolous, Parmotrema tinctorum grows equally well on trunks and branches. Phorophytes are various native and introduced trees and shrubs belonging to the genera Acacia , Agauria , Cocos , Cryptomeria , Cyathea , Dombeya , Erica , Euodia , Hubertia , Melicope , Molinea , Monimia , Pandanus , Quercus , Sideroxylon , and Weinmannia . The endemics Acacia heterophylla and Erica reunionensis are the most frequent phorophytes (respectively 21 and 15 % of the collections). The species was found from sea level to the upper limit of cloud forests in various anthropogenic and natural lowland (coastal thicket, dry forest), submontane (leeward and windward rainforests, Pandanus wet thicket, mesic forest), and montane (leeward and windward rainforests, Acacia forest, Erica thicket) habitats. Bioclimatic features of the localities are also diverse ( Fig. 41B ): bioclimates pluviseasonal tropical and pluvial tropical, thermotype belts from lower thermotropical to upper mesotropical (336 ≤ It ≤ 680), ombrotype belts from upper dry to ultrahyperhumid (2.9 ≤ Io ≤ 27.6). While Parmotrema tinctorum appears to be very tolerant regarding rainfall regime, it seems, on the other hand, to be more selective in terms of temperature. On Réunion, this lichen has not been found above 1850 m elev., where the average annual temperature falls below ca. 13°C (our own calculation from data available in Jumaux et al . 2011 ). The few available data from tropical islands with high relief confirm that P. tinctorum does not occur at high elevations. In the Hawaiian Islands, it ranges from 0 to 1250 m ( Smith 1993 ); in New Guinea , from 580 to 1900 m ( Louwhoff & Elix 1999 ); in Borneo (Mount Kinabalu), from 700 to 1650 m ( Sipman 1993 ); in Taiwan , it does not exceed the montane belt ( Lai 2001 ). The need for an average annual temperature of over ca. 13°C would be moreover consistent with the limits of the species distribution in temperate zones, such as in East Asia , Australia , New Zealand , or the eastern USA ( Elix 1994 , Brodo et al . 2001 , Chen et al . 2005 , Galloway 2007 , Jayalal et al . 2013 , GBIF 2023a ). Notes :—Within the genus Parmotrema , four species with isidia and a medulla containing only lecanoric acid as a major extrolite are currently recognized, and primarily distinguished on the basis of the morphology of the isidia: thin (ca. 0.1 mm thick), papillate granular to cylindrical in P. tinctorum , inflated ( 0.2–0.5 mm thick) and ± papillate in P. pseudotinctorum (Abbayes) Hale , coarsely granular in P. stuhlmannii (C.W. Dodge) Krog & Swinscow , granularglobose and pustulate in P. pustulotinctum Spielmann & Bungartz ( des Abbayes 1951 , Dodge 1959 , Hale 1965a , Krog & Swinscow 1981 , Bungartz & Spielmann 2019 ). Depending on the authors, however, there are divergent opinions on the recognition of these species. For example, Hale (1965a) and Roca-Valiente et al . (2013) put P. stuhlmannii in synonymy with P. pseudotinctorum , whereas Krog & Swinscow (1981) and Farkas & Muhoro (2022) recognised P. stuhlmannii as a separate species, mainly on account of its narrower lobes and strongly fastened thallus but treated P. pseudotinctorum as a synonym of P. tinctorum . A molecular phylogeny study of P. tinctorum s. lat. using two loci showed the existence of two distinct and well-supported clades ( Roca-Valiente et al . 2013 ). On the basis of isidium morphology, one was assigned to P. tinctorum s. str. (‘thin cylindrical isidia’), the other to P. pseudotinctorum , including P. stuhlmannii (‘thick coarse isidia’). It appears however that the sampling of that study did not cover the whole morphological diversity of isidia encountered in the P. tinctorum group, as for example the isidia ‘partly or wholly dissolved into granular soredia’ reported by Krog & Swinscow (1981) , also found on Réunion and Mauritius . Molecular inferences with our 3-locus dataset resolved our 13 accessions (from Mauritius , Réunion and Rodrigues) as a strongly supported clade, with P. austrosinense (a sorediate species with the same extrolite as P. tinctorum ) as a sister group ( Fig. 3 ). Species delimitation methods used in this study support two species with Stacey and a single one with bPP. Our detailed phenotypical and ecological studies of these specimens do not support recognition of two different taxa. In particular, sequences of specimens with ± sorediate granular isidia were not resolved as a different taxon. We thus opt for a single species in this work, with three ITS variants ( Table 3 ), pending further analysis on a much wider scale. Specimens examined :— FRANCE . Réunion : Bras-Panon, sentier de la Caroline, elev. 760 m , 21°01’42”S , 55°37’08”E , in disturbed windward submontane rainforest with patches of Pandanus wet thickets, on bark of a branch of Pandanus montanus , 15 August 2017 , D. Masson 974.4956 (Hb. DM); Cilaos, western side of Bonnet Carré, on GR R1 trail, elev. 1330 m , 21°07’31”S , 55°27’48”E , in disturbed leeward montane rainforest, in an overall westerly orientation, subvertical face of a large volcanic rock, 18 August 2015 , D. Masson 974.4718 (LG); ibid ., Ravine des Calumets, elev. 1140 m , 21°09’34”S , 55°29’26”E , in the bottom of a ravine, in an overall south orientation, in a disturbed submontane mesic forest, on a 75° sloping face, a little shaded and facing NE, of a large basaltic rock, 21 August 2012 , D. Masson 974.3952 (LG); ibid ., Plateau des Chênes, elev. 1320 m , 21°07’36”S , 55°28’29”E , picnic area with introduced trees ( Cryptomeria , Pinus , Quercus …), on bark of the trunk of an old Quercus robur , 18 August 2015 , D. Masson 974.4720 (Hb. DM); Entre-Deux, sentier de la Grande Jument , elev. 790 m , 21°13’38”S , 55°28’57”E , in disturbed leeward submontane rainforest with numerous Psidium cattleianum , in an overall SSW orientation, on bark of a branch of a large Agauria sp. , 16August 2015 , D. Masson 974.4657 (Hb. DM); ibid ., elev. 840 m , 21°13’28”S , 55°28’56”E , in disturbed leeward submontane rainforest, in an overall south orientation, on bark of a branch of an undetermined tree, 16 August 2015 , D. Masson 974.4658 (LG); ibid ., elev. 1115 m , 21°12’46”S , 55°28’59”E , in leeward montane rainforest, in an overall south orientation, on bark of a branch of Agauria sp. , 16 August 2015 , D. Masson 974.4666 (LG); La Plaine-des-Palmistes, Ligne Deux Mille en Dessous, elev. 870 m , 21°07’03”S , 55°39’05”E , in submontane Pandanus wet thicket, in an overall NE orientation, on bark of a branch of Pandanus montanus , 18 August 2017 , D. Masson 974.5000 (Hb. DM); La Possession, Dos d’Âne, sentier des Lataniers, elev. 1140 m , 20°58’30”S , 55°23’31”E , in disturbed leeward submontane rainforest with numerous Psidium cattleianum , on a subvertical and NW oriented face of a basalt rock, 17 August 2012 , D. Masson 974.3861 (Hb. DM); ibid ., Roche Verre Bouteille, elev. 1270 m , 20°59’26”S , 55°23’20”E , in Erica montane thicket, on a 60° inclined and south oriented face of a volcanic rock, 04 August 2005 , D. Masson 974.1932 (Hb. DM); ibid ., La Grande Montagne , sentier des Lataniers, elev. 1330 m , 20°58’17”S , 55°23’30”E , in leeward montane rainforest, in an overall NW orientation, on bark of a trunk of Erica reunionensis , 19 August 2015 , D. Masson 974.4731 (LG); ibid ., Piton Grand Bazar, elev. 1330 m , 20°58’25”S , 55°23’27”E , in leeward montane rainforest, in an overall NW orientation, on bark of a trunk of Weinmannia sp. , 19 August 2015 , D. Masson 974.4743 (Hb. DM); ibid ., Cirque de Mafate, sentier Scout, elev. 1510 m , 21°02’50”S , 55°26’44”E , in leeward montane rainforest, on bark of a trunk of an undetermined tree, 24 July 2005 , D. Masson 974.1715 (Hb. DM); ibid ., Plaine des Tamarins, elev. 1760 m , 21°04’49”S , 55°26’23”E , in grazed Acacia montane forest, on bark of Acacia heterophylla , 27 July 2005 , D. Masson 974.1794 (Hb. DM); ibid ., elev. 1760 m , 21°04’49”S , 55°26’30”E , in grazed Acacia montane forest, on bark of a branch of Acacia heterophylla , 22 August 2017 , D. Masson 974.5087 (LG); ibid ., elev. 1760 m , 21°04’44”S , 55°26’36”E , in grazed Acacia montane forest, on bark of a branch of Acacia heterophylla , 22 August 2017 , D. Masson 974.5072 (Hb. DM); ibid ., elev. 1755–1765 m , 21°05’00”S , 55°26’16–19”E, in grazed Acacia montane forest, on bark of a branch of Acacia heterophylla and on a 50° inclined and west oriented face of a basalt rock, 22 August 2017 , D. Masson 974.5078 (LG), 974.5086 (Hb. DM); Les Avirons, route forestière 6 du Tévelave, elev. 1050 m , 21°12’04”S , 55°21’24”E , in disturbed leeward submontane rainforest, on bark of a trunk of Cryptomeria japonica , 10 April 2003 , D. Masson 974.0287 (Hb. DM); Le Tampon, forêt de Notre-Dame de la Paix, le Belvédère, elev. 1720 m , 21°15’51”S , 55°36’09”E , at the edge of a leeward montane rainforest, on bark of undetermined tree, 17 July 2005 , D. Masson 974.1413 (Hb. DM); ibid ., Notre-Dame de la Paix, elev. 1570 m , 21°14’24”S , 55°35’05”E , in Acacia montane forest, on bark of Acacia heterophylla , 23 July 2005 , D. Masson 974.1674 (REU), 974.1675 (Hb. DM); L’Étang-Salé, Chemin Canal, elev. 950 m , 21°13’13”S , 55°22’16”E , on a ridge in leeward submontane rainforest, on bark of a horizontal trunk of Erica reunionensis , 27 August 2017 , D. Masson 974.5136 (LG); Petite-Île, Manapany les Hauts, elev. 800 m , 21°19.6’S , 55°35.2’E , open picnic place with some mature Cryptomeria trees, shrubs and mixed trees, including orchard with fruit trees, on Cryptomeria japonica , 07 June 2008 , P. & B. van den Boom 40804 ( Hb. van den Boom); Saint-André, forêt de Dioré, elev. 825 m , 20°59’36”S , 55°34’55”E , in windward submontane rainforest, on bark of a branch of Pandanus montanus , 21 August 2017 , D. Masson 974.5055 (Hb. DM); ibid ., Forêt Communale, elev. 770 m , 20°59’39”S , 55°35’33”E , in windward submontane rainforest, on bark of a branch of an undetermined tree, 28 July 2005 , D. Masson 974.1804 (Hb. DM); Saint-Benoît, Pointe du Bourbier, elev. 20 m , 21°01’13”S , 55°42’13”E , coastal recreation area, on bark of a trunk of Pandanus utilis , 12 August 2013 , D. Masson 974.4217 (Hb. DM); ibid ., Piton de Bébour, elev. 1430 m , 21°07’38”S , 55°33’39”E , in windward montane rainforest, on bark of a branch of an undetermined tree, 07 April 2003 , D. Masson 974.0155 (Hb. DM); ibid ., forêt de Bébour, sentier de Takamaka, elev. 1360 m , 21°06’23”S , 55°33’58”E , in windward montane rainforest, on stipe of a dead Cyathea sp. , 29 July 2005 , D. Masson 974.1838 (Hb. DM); ibid ., forêt de Bébour, sentier de la Rivière des Marsouins, elev. 1320 m , 21°06’47”S , 55°33’47”E , in windward montane rainforest, along a river, on a shaded volcanic rock, 15 April 2003 , D. Masson 974.0415 (Hb. DM); Saint-Denis, sentier de la Roche Écrite, elev. 1415 m , 20°57’47”S , 55°26’25”E , in windward montane rainforest, in an overall north orientation, on bark of the trunk of a dead Erica reunionensis , 20 August 2015 , D. Masson 974.4750 (Hb. DM); ibid ., elev. 1625 m , 20°58’29”S , 55°26’35”E , in Acacia montane forest, in an overall NW orientation, on bark of a trunk of Melicope obtusifolia , 20 August 2015 , D. Masson 974.4764 (Hb. DM); ibid ., elev. 1710 m , 20°58’43”S , 55°26’41”E , in Acacia montane forest with Nastus borbonicus , in an overall NW orientation, on bark of a trunk of Acacia heterophylla , 20 August 2015 , D. Masson 974.4767 (LG); ibid ., Plaine d’Affouches, elev. 1715–1720 m , 20°59’14–15”S, 55°26’00–02”E, in Acacia montane forest with Nastus borbonicus and Cyathea glauca , on bark of a trunk of an old Acacia heterophylla and branches of Erica reunionensis , 18 August 2012 , D. Masson 974.3871 (REU), 974.3872, 974.3885 , 974.3886 (Hb. DM); Saint-Joseph, Piton du Rond, elev. 1380 m , 21°17’57”S , 55°36’26”E , on a ridge in leeward montane rainforest, on bark of a trunk of Molinea alternifolia , 18 August 2013 , D. Masson 974.4309 (Hb. DM); ibid ., Grand Coude, elev. 1345 m , 21°16’35”S , 55°37’44”E , in disturbed windward montane rainforest, on bark of a branch of Sideroxylon borbonicum , 24 August 2017 , D. Masson 974.5111 (LG); ibid ., elev. 1455 m , 21°16’31”S , 55°38’01”E , in windward montane rainforest, on bark of a branch of Monimia rotundifolia , 24 August 2017 , D. Masson 974.5119 (Hb. DM); Saint-Leu, le Piton Saint-Leu, on basalt rock, on the roadside, June 1957 , J. Bosser 11348 (REN 000076); Saint-Louis, Les Makes, Bois Bon Accueil, elev. 1010 m , 21°11’56”S , 55°23’56”E , in leeward submontane rainforest, in an overall south orientation, on bark of a trunk of a young Weinmannia sp. , 28 August 2017 , D. Masson 974.5145 (Hb. DM); ibid ., elev. 1145 m , 21°11’38”S , 55°24’06”E , in leeward submontane rainforest, on bark of a trunk of an undetermined tree, 28 August 2017 , D. Masson 974.5149 (LG); ibid ., forêt des Makes, elev. 1845 m , 21°10’39”S , 55°25’13”E , in cultivated Acacia montane forest, in an overall SSW orientation, on bark of a branch of Hubertia ambavilla , 19 August 2013 , D. Masson 974.4331 (Hb. DM); Saint-Paul, sentier F. Francia, elev. 1565 m , 21°01’49”S , 55°22’28”E , in Acacia montane forest, on bark of Acacia heterophylla , 31 July 2005 , D. Masson 974.1863 (Hb. DM); Saint-Pierre, Piton de Mont Vert, elev. 585 m , 21°19’37”S , 55°32’28”E , in lowland dry forest, on bark of trunks of Pandanus sylvestris and undetermined trees, 19 August 2017 , D. Masson 974.5011 (REU), 974.5012 (LG), 974.5013 (Hb. DM); ibid ., forêt du Haut de Mont Vert, elev. 1540 m , 21°17’13”S , 55°35’59”E , disturbed area with former grasslands and remnants of leeward montane rainforest, on bark of a branch of an isolated Acacia heterophylla , 17 August 2017 , D. Masson 974.4979 (LG); Sainte-Marie, Plaine des Fougères, elev. 1380 m , 20°59’02”S , 55°30’50”E , in Acacia montane forest, in an overall NE orientation, on bark of a branch of Dombeya reclinata , 31 August 2012 , D. Masson 974.4162 (REU), 974.4163 (Hb. DM); ibid ., elev. 1465 m , 20°58’51”S , 55°30’00”E , in windward montane rainforest, in an overall north orientation, on ± mossy bark of Erica reunionensis , 30 August 2012 , D. Masson 974.4138 (Hb. DM); Sainte-Rose, le Port, elev. 10 m , 21°07’32”S , 55°47’21”E , coastal recreation area, on bark of a trunk of Pandanus utilis , 12 April 2003 , D. Masson 974.0290 (Hb. DM); ibid ., la Marine, elev. 10 m , 21°07’31”S , 55°47’32”E , disturbed coastal thicket, on bark of a trunk of Pandanus utilis , 15 August 2013 , D. Masson 974.4244 (Hb. DM); Sainte-Suzanne, les Hauts de la Perrière, elev. 765 m , 20°58’44”S , 55°33’52”E , on roadside in disturbed leeward submontane rainforest, in an overall NE orientation, on bark of a branch of an undetermined tree, 11 August 2015 , D. Masson 974.4597 (LG); ibid ., le Grand Hazier, elev. 75 m , 20°54’19”S , 55°35’21”E , in a vanilla plantation, on bark of Cocos nucifera , 24 October 2012 , J.L. & B. Martin 01 (Hb. DM); Salazie, Piton d’Enchain, elev. 1350 m , 21°02’35–37”S, 55°29’50–53”E, in windward montane rainforest, on bark of Melicope borbonica and an undetermined tree, 13 April 2003 , D. Masson 974.0300 (REU), 974.0358 (Hb. DM); ibid ., Mare d’Affouches, elev. 830 m , 21°02’59”S , 55°29’46”E , in disturbed thicket with Psidium cattleianum and Erica reunionensis , on a mossy volcanic rock, 13 April 2003 , D. Masson 974.0293 (Hb. DM); ibid ., D52 road between Mare à Citrons and Mare à vieille Place, elev. 700 m , 21°02’00”S , 55°31’22”E , in a cultivated area (mainly sugar cane), on large exposed rocks of volcanic breccia, 14 April 2003 , D. Masson 974.0437 (Hb. DM); ibid ., forêt de Bélouve, elev. 1595 m , 21°04’11”S , 55°31’58”E , in cultivated Acacia montane forest, in an overall NE orientation, on bark of a trunk of Erica reunionensis , 25 August 2013 , D. Masson 974.4454 (LG); ibid ., near Gîte de Bélouve, elev. 1520 m , 21°03.5’S , 55°32.5’E , area with mature Acacia heterophylla trees in mixed forest along road and path, on Acacia heterophylla , 27 May 2008 , P. & B. van den Boom 39864 ( Hb. van den Boom). MAURITIUS . Moka District : Réduit, trees close to the Mauritius Herbarium building, elev. 310 m , 20.23554°S , 57.4944°E , on Pinus , 30 August 2019 , P. Diederich 18694 & D. Ertz (Hb. P. Diederich); ibid ., State House Park, elev. 280 m , 20.22875°S , 57.48705°E , on Cinnamomum , Ficus microcarpa , and a wall, 30 August 2019 , P. Diederich 18703, 18713, 18724 & D. Ertz (Hb. P. Diederich); Pamplemousses District : Pamplemousses , Jardin botanique Sir Seewoosagur Ramgoolam, elev. 80 m , 20.10631°S , 57.58133°E , on bark of trees, 28 July 2016 , P. Diederich 18233, 18266 (Hb. P. Diederich); Plaines Wilhems District : Curepipe, Curepipe Botanic Gardens, elev. 565 m , 20.32505°S , 57.51389°E , on bark of trees, 09 September 2019 , P. Diederich 19459 & D. Ertz (Hb. P. Diederich); ibid ., elev. 565 m , 20.32442°S , 57.51361°E , on bark of trees, 30 July 2016 , P. Diederich 18299, 18595 (Hb. P. Diederich); Rivière Noire District : Black River Gorges National Park, along trail to Piton de la Petite Rivière Noire , elev. 630–700 m , 20.42133°S , 57.41947°E , on the bark of trees, 05 August 2016 , P. Diederich 18451 (Hb. P. Diederich); ibid ., Chamarel, near the Seven Coloured Earths, future ecotourism park ‘Ebony Forest’, around the viewpoint, elev. 350 m , 20.43034°S , 57.37412°E , on the bark of trees, 08 August 2016 , P. Diederich 18543 (Hb. P. Diederich); Rodrigues : Grande Montagne Nature Reserve, elev. 330 m , 19.70512°S , 63.46596°E , on exposed rocky outcrop surrounded by forest rich in Pandanus trees, 04 September 2019 , P. Diederich 19026, 19517 & D. Ertz (Hb. P. Diederich); ibid ., elev. 330–360 m , 19.70611°S , 63.46447°E , on a rock, 04 September 2019 , P. Diederich 19003 & D. Ertz (Hb. P. Diederich). Specimens not examined, but included in the distribution map :— FRANCE . Réunion : Cilaos , Bassin des Salazes , where the road crosses Ravine Pissa , elev. 1190 m , 21.12°S , 55.45°E , 02 October 1996 , leg. & det. H. Krog ( RE33 /4, RE33/5) & E. Timdal (O); ibid ., along trail ( GR R2 ) in canyon just W of Cilaos town , elev. 1150 m , 21.13°S , 55.47°E , 02 October 1996 , leg. & det. H. Krog ( RE34 /1) & E. Timdal (O); ibid ., along road towards Bras Sec , at intersection with canyon of Bras de Benjoin , elev. 1360 m , 21.13°S , 55.48°E , 02 October 1996 , leg. & det. H. Krog ( RE35 /8) & E. Timdal (O); Saint-Benoît , forêt de Bébour , the ‘kiosque’ between Ravine Pavée and Ravine Misère , elev. 1510 m , 21.10°S , 55.54°E , 30 September 1996 , leg. & det. H. Krog ( RE27 /4) & E. Timdal (O); Saint-Denis , along road towards Plaine d’Affouches , above Bras Citron , at point where road meets track, elev. 1220 m , 20.96°S , 55.40°E , 26 September 1996 , leg. & det. H. Krog ( RE08 /6, RE08/7) & E. Timdal (O) .