Dimelaena altissima M. Ai & Xin Y. Wang

Dimelaena altissima (H. Magn.) M. Ai & Xin Y. Wang, Phytotaxa 574 (4): 259 (2022) Fig. 1 Description. Thallus crustose, areolate-placodioid, up to 5 cm across, well-defined, lobate. Areoles: strongly convex, rounded to irregular, 0.5–1 mm in diameter, radiating towards margins, up to 1.5 mm long, 0.5 mm wide. Color: yellowish green to yellowish white when dry, no change when wet. Upper cortex: 2 - layered, outer greyish, 10‒20 μm thick, inner hyaline, 20‒30 μm thick, cells rounded, 5‒8 μm in diameter. Algal layer: continuous, even, 60‒80 μm thick, photobiont chlorococcoid, cells globose, 9‒13 μm in diameter. Medulla: 90‒120 μm thick, hyphae hyaline, 3‒4 μm wide. Apothecia: frequent, lecanorine, 1‒3 per areole. Disc: round, black, pruinose, plane to concave, 0.2‒0.7 mm in diameter. Margins: thick, persistent, concolorous to thallus. Epihymenium: brown, 10‒15 μm tall. Hymenium: hyaline, 40‒50 μm tall. Hypothecium: hyaline, 60‒70 μm tall. Paraphyses: septate, branched, capitate, 1‒2 μm wide apically. Asci: hyaline, clavate, 40‒50 × 15‒20 μm. Ascospores: brown, 1 - septate, 9‒12 × 5‒8 μm. Chemical study. K + ve (yellow), C-ve, KC + ve (yellow). Usnic acid and norstictic acid detected through TLC. Phylogenetic analysis. For phylogenetic analysis, sequences of the genus Dimelaena were retrieved from GenBank based on their similarity to our sequences and those used in a study on the phylogeny of Dimelaena by Ai et al. (2022). Due to the limited availability of Dimelaena sequences, some sequences of the closest genus Buellia were also included in constructing the phylogenetic tree. The final aligned file was comprised of 525 nucleotides, among which 345 were conserved, 180 were variable, 161 were parsimony-informative, and 19 were singleton variants. Physcia aipolia (Ehrh. ex Humb.) Fürnr. (MK 811989 and MK 812087) was chosen as an outgroup. In our analysis, the newly generated sequences of Dimelaena altissima from Pakistan (KH- 608, KH- 609, and BST- 03) grouped within a single clade alongside other sequences of the same species (MZ 229869, MZ 229873, MZ 229883, and MZ 229884), receiving strong support (90 % ML), thus confirming their identification as D. altissima (Fig. 2). Additionally, D. altissima shows a sister relationship with D. oreina, which also forms a distinct clade with high bootstrap support (83 % ML). Notes. Dimelaena altissima is distinguished by its yellowish-green, epruinose crustose thallus with flat marginal lobes, along with irregularly rounded, innate apothecia that have indistinct margins (Ai et al. 2022). The morphological comparison confirms the identity of the Pakistani taxon as D. altissima as it shares same morpho-anatomical characteristics with D. altissima described from China, such as a crustose thallus with radiate-plicate margins and lecanorine immersed apothecia (Ai et al. 2022). It is morphologically and phylogenetically closely related to D. oreina but differs from it by lacking well-defined apothecial margins and convex marginal lobes (Ai et al. 2022). It is the first report of D. altissima from Pakistan. Habitat and ecology . The collections (KH- 602 & KH- 608) were found in dry temperate climate, in an open situation exposed to sun and rain, at an altitude of 841 m a. s. l., temperature typically varies from - 8 ° C to 28 ° C, with annual rainfall varying between 700–800 mm. Whereas the other collection (BST- 03) was found at an elevation above 4,173 m, on rock, in a temperate climate with minimum and maximum temperatures of - 8 ° C and 35 ° C, respectively. The region is characterized by hilly topography, with annual rainfall varying between 90 and 150 mm and heavy snowfall during the winter months. Distribution. This species was previously documented from China (Ai et al. 2022) and is now recorded from Pakistan for the first time. Materials examined. Pakistan ∙ Khyber Pakhtunkhwa Province, Kohistan, Dassu; 35°35.0'N, 73°37.0'E; alt. 841 m a. s. l.; 11 Sep. 2020; K. Habib & A. N. Khalid leg.; on rock; KH- 602 & KH- 608, ITS GenBank accession numbers PQ 113699 and PQ 113700. Pakistan ∙ Gilgit-Baltistan, District Diamer, Babusar Top; 35°08.8'N, 74°02.9'E; alt. 4,173 m a. s. l.; 28 Aug. 2023; U. F. Ahmad, M. Usman & A. N. Khalid leg.; on rocks; in moist temperate forest; BST- 03, ITS GenBank accession number PQ 113698.