Usnea lapponica Vain.

Ahmad, Uswa Fatima, Zulfiqar, Rizwana, Naheed, Muqaddas, Nadeem, Muhammad, Habib, Kamran, Niazi, Abdul Rehman & Khalid, Abdul Nasir, 2024, A systematic study of some lichenized fungi from Pakistan using nrITS marker, Italian Botanist 18, pp. 75-96 : 75-96

Usnea lapponica Vain. , Meddn Soc. Fauna Flora Fenn. 48: 173 (1925) [1924]

Fig. 9

Description.

Thallus fruticose, pendent, tufted, erect, attached by a basal holdfast, up to 6 cm long. Branches: irregular, black at tips, segments terete, anisotomic dichotomous, longitudinally cylindrical, thin toward apex, up to 1 mm in diameter. Papillae: present on main branches, unevenly distributed, frequent. Color: thallus pale yellowish green to pale grey-green when dry, no change when wet. Cortex: prosoplectenchymatous, inner layer hyaline, outer greyish brown, 10–25 µm thick. Photobiont: 8–14 µm in diameter, globose to sub-globose. Medulla: loosely arranged, hyphae white. Soralia: superficial, discrete, excavated, mostly on thick branches, rounded to slightly irregular, soredia farinose and white.

Chemical study.

K + ve (yellow), C-ve, KC + ve (yellow). Usnic acid and salazinic acid were detected through TLC.

Phylogenetic analysis.

For phylogenetic analysis, sequences of the genus Usnea were retrieved from GenBank based on their similarity to our sequences. A total of 31 ITS nrDNA sequences were analyzed during this study. The final aligned file was comprised of 503 nucleotides, among which 397 were conserved, 104 were variable, 88 were parsimony-informative, and 16 were singleton variants. Protousnea magellanica (Mont.) Krog ( DQ 985192 and KR 995309 ) was chosen as an outgroup. In the ITS phylogram, the sequence of the Pakistani Usnea lapponica specimen forms a clade along with sequences of the same taxon reported from Austria ( KJ 406267 ), India ( KJ 406266 ), Sweden ( KJ 406265 ), and Switzerland ( KX 132930 ) (Fig. 10 ).

Notes.

Usnea lapponica is characterized by an erect to pendent fruticose thallus with deeply excavated soralia and farinose soredia ( Halonen et al. 1998). For morphological comparison, the characteristics of the Pakistani sample were compared with the description of U. lapponica given by Halonen et al. (1999), which shows that both of them share the same characteristics such as a highly branched thallus, slender branches, a thinner cortex, and a thicker central axis but differ from each other due to having different branching patterns (anisotomic-dichotomous vs. isotomic-dichotomous) ( Halonen et al. 1999).

Habitat and ecology.

Corticolous, found at an elevation above 3,228 m, growing in a cold and dry temperate mountainous region, with a mean maximum and minimum temperature of 22 ° C and - 18 ° C, respectively, and an annual rainfall varying between 254 and 400 mm. The dominant vegetation includes Picea smithiana (Wall.) Boiss , Pinus wallichiana A. B. Jacks. , and Betula utilis D. Don.

Distribution.

This species is widespread in Europe, Finland, Iran, North America and Russia ( Halonen et al. 1999; Seaward et al. 2004). From Pakistan, it is reported for the first time.

Material examined.

Pakistan ∙ Gilgit-Baltistan, District Gilgit, Naltar Valley, Blue Lake ; 36°14.2'N, 74°06.1'E; alt. 3,228 m a. s. l.; 30 Aug. 2023; U. F. Ahmad, M. Usman & A. N. Khalid leg.; growing on bark; NL- 1, ITS GenBank accession number PQ 113701 .

Figures

Figure 9. Usnea lapponica A, B fruticose thallus C branches of the thallus D cross-section of the branch showing central strand.

Figure 10. Molecular phylogenetic analysis of Usnea spp. by maximum likelihood (ML) method based on nrITS sequences. Bootstrap values > 50 % based on 1000 replicates for ML are shown above the branches and novel sequence generated during this study is in bold.