Chrysothrix susquehannensis Lendemer & Elix

  • Family

    Chrysothricaceae (Ascomycota)

  • Scientific Name

    Chrysothrix susquehannensis Lendemer & Elix

  • Primary Citation

    Two new species of Chrysothrix from eastern North America.
    Opusc. Philolichenum 8: 51-58. 10/04/2010

  • Type Specimens

    Specimen 1: Holotype -- J. C. Lendemer 19364

  • Description

    Type: U.S.A. PENNSYLVANIA. LANCASTER CO.: E slopes above Susquehanna River, 0.25-0.5 mi N of confluence of Tucquan Creek and Susquehanna River, schist outcrops/bluffs with oak-gum-pine forest, 8.viii.2009, on humus and mosses on sheltered vertical rock face, J.C. Lendemer 19364 (NY, holotype; hb. Kalb, isotype).

    Description: (from Lendemer & Elix 2010) - Thallus crustose, leprose, dull lemon-yellow to greenish, with the granules sparsely distributed at first, eventually dividing and accumulating into small overlapping heaps that become confluent and form small, poorly defined, 0.1-0.3 mm thick, rosettes with diffuse margins; granules ecorticate, 40-90 µm in diameter, round, with a layer of gelatinized hyaline hyphae surrounding the algal core; hyphae hyaline, 2-4 µm wide, septate, thin walled; photobiont chlorococcoid, cells globose, 9-11 µm in diameter. Apothecia and pycnidia unknown.

    Etymology: (from Lendemer & Elix 2010) - The epithet “susquehannensis” refers to the Susquehanna River which flows through Pennsylvania on its way to the Chesapeake Bay.

    Illustrations: Color: Lendemer and Elix (2010, Opuscula Philolichenum, 8: 57, plate 4). Scanning electron micrographs: Lendemer and Elix (2010, Opsucula Philolichenum, 8: 56, plate 3).

    Chemistry: (from Lendemer & Elix 2010) - Rhizocarpic acid (major), epanorin (minor), lecanoric acid (minor), atranorin (minor), conrhizocarpic acid (trace). Spot tests: K-, C+ pink/red, KC+ pink/red, P-, UV+ orange.

    Ecology and distribution: (from Lendemer & Elix 2010) - Chrysothrix susquehannensis occurs on small moss cushions and pockets of soil or organic matter clinging to precipitous shaded vertical rock outcrops. It is known only from the type locality although it is probable that more populations occur in the immediate vicinity. Unfortunately the extensive sheer rock faces inhabited by the species are almost impossible to access. The type locality and adjacent areas along the river are well known for hosting a unique and varied flora of vascular plants which was well studied in the late 1890's and early 1900's by Arthur A. Heller and John K. Small (Heller 1893, Small & Carter 1913). Many unusual lichen species also occur in the area including several at the edge of their geographic range (Heller 1893, Lendemer in press.). It is unlikely that the lack of additional records of this species outside of the lower Susquehanna River valley is due to collection bias because the region was intensively studied in the past by local botanists and in a recent detailed survey by the first author. Further, this species was not encountered by Harris and Ladd (2008) during their revision of the genus Chrysothrix in eastern North America. Given its apparent rarity and restricted distribution, C. susquehannensis should probably be given protective status at the state or federal level.

    Discussion: (from Lendemer & Elix 2010) - The new taxon is distinguished from all other known Chrysothrix species by the production of lecanoric acid together with rhizocarpic acid and epanorin. Among the North American species of Chrysothrix this new species is distinguished by its unique chemistry as well as its ecology. It occurrs on moss cushions and organic matter whereas the other North American species occur directly on rock or bark. It is morphologically similar to C. chlorina (Ach.) J.R. Laundon and C. onokoensis (Wolle) R.C. Harris & Ladd in the size of the thalline granules, but differs from those species in having a thinner thallus (0.1-0.3 mm vs. ca. 1.0 mm thick).

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