Parmotrema appendiculatum (Fée) Hale (1974a: 334) 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 : 116

Parmotrema appendiculatum (Fée) Hale (1974a: 334) MycoBank no. 343010

Parmelia appendiculata Fée (1837: 118) MycoBank no. 397153

Type:— FRANCE. La Réunion [‘Bourbon’], s.d., unknown collector (G, lectotype [image!]; G, isolectotype [image!]; designated by Hale 1974b) .

This taxon is morphologically similar to Parmotrema disparile . The lobe margins and apothecia bear corniculate laciniae and the apothecial discs are imperforate. Hale (1965a, 1974b) and Krog & Swinscow (1983) stated that the lobe margins were ciliate, but the presence of genuine marginal cilia was not cited by Fée (1837), Nylander (1860) or Müller (1887), and no cilia are visible in the photographs of the type collection. Ascospores of P. appendiculatum are apparently larger than those of P. disparile , according to the dimensions provided by Nylander (1860: 381): 27– 31 × 11–18 µm. However, the main difference between the two species is their medullary chemistry: barbatic acid and secalonic acid A in the medulla of P. appendiculatum ( Hale 1974b, Krog & Swinscow 1983, labels of the type collection), protocetraric acid and ± an unknown yellow pigment in the medulla of P. disparile ( Table 9).

According to Fée(1837),the type collection originates from Réunion (‘Bourbon’),from tree branches.Unfortunately, no locality, collection date or collector name was provided, and it cannot be guaranteed that the collection actually comes from Réunion. This macrolichen has never been found on this island, or elsewhere. The report by des Abbayes (1956) from Madagascar refers to P. disparile (see the entry for P. odontatum ), and the report from Mauritius ( Dodge 1959) most probably belongs to another species, the sterile specimen involved having ‘rather close, 2–3 mm long’ marginal cilia, as described by Dodge.