Two new Gyalolechia species (Teloschistaceae) from Helan Mountain in China and an identification key for this genus

Helan Mountain, located in northwest China, is the core area of the Alxa Ordos Center, one of the eight major biodiversity centers in China. Two new species, Gyalolechia pustutata D. L. Niu and Gyalolechia farinosa D. L. Niu, from Helan Mountain, China, are described and illustrated based on morphological and chemical analyses and molecular results of ITS sequences. Gyalolechia pustutata is characterized by smaller, single-celled ascospores (8–10 × 3–5 µm), smaller pustulae-like schizidia, and distinct marginal lobes.

Gyalolechia farinosa is characterized by a powdery, rough upper surface with uneven pruisa, an upper cortex with numerous crystals, and one-septate, ellipsoid or broader ellipsoid ascospores. The two new species are compared with similar species, and their phylogenetic position and ecological distribution are discussed. An identification key is provided for the genus Gyalolechia in China.