Parmotrema cooperi (J. Steiner & Zahlbr.) Sérus. (1984: 4) 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 : 32

Parmotrema cooperi (J. Steiner & Zahlbr.) Sérus. (1984: 4) MycoBank no. 107091

Parmelia cooperi J. Steiner & Zahlbr. (1926: 528) MycoBank no. 397385

Type:— SOUTH AFRICA. Kapland , Kapprana, 1813, Cooper s.n. (W, n.v., lectotype; H, M, UPS, US [image!], isolectotypes; designated by Sérusiaux 1984) .

( Fig. 13 )

Thallus foliose, moderately adnate, subcoriaceous to coriaceous, often large, up to 20 × 22 cm. Lobes rounded, imbricate, irregularly branched, 5–20 mm wide, rarely plane, frequently ascending and irregularly convolute when sorediate, with margins undulated, often crenate, ciliate ( Fig. 13C ). Cilia black, sparse to moderately dense, simple or 1–2 times branched, up to 6.5 mm long. Upper surface pale grey, faintly effigurate white-maculate, smooth near lobe tips but often verruculose and reticulated cracked in the older parts, sorediate, lacking schizidia, pustules, dactyls, phyllidia and isidia; regenerative lobules occasionally present in older parts. Soralia marginal at first, then rapidly extending submarginally on revolute and suberect lobe apices ( Fig. 13D ); rarely orbicular submarginal. Soredia granulose, (40)– 53.3 –(70) µm in diameter (n = 90, from 3 specimens, SD = 7.8 µm), darkening and frequently clumping together in dense, rounded clusters with age. Medulla white throughout. Lower surface smooth to rugulose, black and more or less mat centrally (rarely to the margin), with a shiny, erhizinate marginal zone (ca. 3–13 mm wide), chestnut brown, sometimes mottled with ivory white at the sorediate lobes. Rhizines concolor to the lower surface, in scattered groups, simple to furcate, up to 2.5 mm long. Apothecia not seen in the specimens examined. Pycnidia occasional, submarginal towards apices; only primordia seen. Conidia not found.

Chemistry:— Spot tests and fluorescence: upper cortex K+ yellow, UV−; medulla K−, C + red, KC + red, P−, UV−. Secondary metabolites ( TLC): upper cortex with atranorin and chloroatranorin; medulla with lecanoric acid.

Geographical distribution:—A species with a predominantly paleotropical distribution ( Louwhoff 2001), but recently reported from tropical America in Mexico ( Egan et al. 2016, León-González & Pérez-Pérez 2020) and in the Galapagos Islands ( Bungartz & Spielmann 2019). In MIOI, present in Madagascar ( des Abbayes 1961, Hale 1965a, Aptroot 1991) and in Réunion (van den Boom et al. 2011). In Réunion, eight localities in six UTM 1× 1 km grid cells (or five UTM 2× 2 km grid cells, Fig. 13A ) are known so far, all located in the leeward part of the island between 1530 and 1760 m elevation. It is the only species of Parmotrema with this distribution pattern on Réunion.

Ecology:—On Réunion, Parmotrema cooperi was only found in leeward Acacia montane forests, natural or cultivated. These are open forests, with undergrowth frequently grazed extensively by livestock. In this habitat, P. cooperi grows on the trunks and branches of the predominant endemic tree A. heterophylla [closely related with the Hawaiian A. koa A. Gray ( Le Roux et al. 2014) ], more rarely on shrubs such as arborescent Erica . Interestingly, this species has so far never been found in the much rainier windward Acacia montane forests. Parmotrema cooperi also occurs in dry, open montane Acacia woodlands in Ethiopia ( Winnem 1975). Mean annual temperatures of the Reunionese localities range from 13 to 18°C, annual rainfall from 1750 to 2700 mm. Bioclimatic features ( Fig. 13B ) can be summarized as follow: bioclimate pluvial tropical, thermotype belt mesotropical (330 ≤ It ≤ 465), ombrotype belts from lower humid to lower hyperhumid (8.1 ≤ Io ≤ 16.7).

Notes:—This species is the only one in the genus Parmotrema with the combination of the following characters: cilia, soredia, and lecanoric acid in the medulla. Parmotrema austrosinense has the same chemistry and a rather similar morphology, but its lobe margins are eciliate.

Specimens examined:— FRANCE. Réunion: La Possession, cirque de Mafate, plaine des Tamarins, elev. 1760 m, 21°04’44”S, 55°26’36”E, in Acacia montane forest, on branch of A. heterophylla , 22 August 2017, D. Masson 974.5071 (Hb. DM); Les Avirons, route forestière 6 du Tévelave, elev. 1530 m, 21°11’05”S, 55°22’19”E, in an exploited Acacia forest, on branch of A. heterophylla , 10 April 2003, D. Masson 974.0286 (Hb. DM); Saint-Louis, forêt des Makes, plateau Goyaves, elev. 1755 m, 21°10’53”S, 55°24’32”E, in an exploited Acacia forest, on trunk of A. heterophylla , 19 August 2013, D. Masson 974.4318 (REU), 974.4319 (Hb. DM); Saint-Paul, route forestière des Tamarins des Hauts-sous-le-Vent, elev. 1740 m, 21°04’18”S, 55°21’42”E, in an exploited Acacia forest, on A. heterophylla , 10 April 2003, D. Masson 974.0241, 974.0244, 974.0246 (Hb. DM); ibid., sentier F. Francia, elev. 1580 m, 21°01’50”S, 55°22’34”E, in Acacia montane forest, on A. heterophylla , 31 July 2005, D. Masson 974.1870 (Hb. DM); ibid., sentier F. Francia, elev. 1565 m, 21°01’49”S, 55°22’28”E, in Acacia montane forest, on A. heterophylla , 31 July 2005, D. Masson 974.1864 (REU), 974.1865, 974.1869 (Hb. DM); ibid., Bras la Source, elev. 1705–1710 m, 21°04’28”S, 55°21’37”E, in Acacia montane forest, on Erica sp. and an undetermined shrub, 02 August 2005, D. Masson 974.1911, 974.1912 (Hb. DM); ibid., sentier Oméga, elev. 1600 m, 21°01’52”S, 55°22’36”E, in Acacia montane forest, on A. heterophylla , 31 July 2005, D. Masson 974.1871 (Hb. DM).

Figures

FIGURE 13. Parmotrema cooperi. 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 974.5071); D: Sorediate lobes with marginal and submarginal soralia at revolute apices (Masson 974.5071). Scale bars:A = 10 km; C = 10 mm; D = 5 mm.