LICHALP

Thelidium gisleri (Müll. Arg) Zschacke

Syn.: Sagedia gisleri Müll. Arg., Verrucaria gisleri (Müll. Arg.) Stizenb.

Lichenised.

Substrate: calciferous rocks

Altitudinal range: from the subalpine belt (potential vegetation: open, taiga-like forests dominated by Larix decidua and/or Pinus cembra and Rhododendron) to the alpine belt (potential vegetation: treeless Alpine grasslands and tundras, to the lower limit of perennial snow and the equilibrium line of glaciers)

Note: a species of the Th. papulare-group with a very thin, whitish-grey thallus, semi-immersed ascomata (to 0.3 mm in diam.) with an involucrellum reaching down about half the perithecium, and 3-septate, narrowly ellipsoid ascospores (less than 40 µm long); on calcareous rocks at high elevations; known from a few localities in the Alps.