Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
Apothecia: 0.2-0.3 mm tall, distinctly stalked capitulum: 0.12-0.19 mm in diam., +globose but often somewhat compressed vertically, regular and smooth, shiny dark brown, rarely black exciple: dark brown, sclerotized; upper part: consisting of 4-6 layers of isodiametric to irregular cells, 4-7 µm diam.; lower part: with sclerotized, isodiametric cells forming a 4-7 µm thick cover over 1-2 layers of periclinally arranged hyphae with rectangular cells; hypothecium: hyaline, 25-36 µm high, consisting of isodiametric to irregular cells asci: cylindrical, 32-45 x 4.5-6 µm ascospores: dark brown, subglobose, non-septate, 4.5-6 x 4-6 µm, with indistinct, very minute ornamentation of irregular folds or cracks visible under light microscope; spore coat: thick and distinct in water mounts of semi-mature spores Spot tests: all parts of ascomata K- Secondary metabolites: none detected. Hosts: Pertusaria (especially P. pertusa), particularly on Quercus or other old deciduous trees; very rarely on Diploschistes or Lecanora on rocks World distribution: Europe and North America Sonoran distribution: southern California and Baja California. Notes: Sphinctrina leucopoda is a very variable species with respect to size and color of the stalk and is sometimes hard to distinguish from S. turbinata, which differs in having non-stalked ascomata, a red, K+ intensified red pigment in the exciple and by having the exciple formed by periclinally arranged, branched hyphae.