Two species of Rinodina: R. marysvillensis and R. archaea, occur commonly on twigs in our area.  Because they are very similar in general appearance, they are shown on the same page.

General Appearance:  (both species) Dark gray-brown to black patches which cannot be separated from the bark; the patches mostly I - 2 cm (3/8- 3/4 in.) or less across.

Thallus: (both species ) Thallus crustose, dull blackish, dark gray or gray-brown when dry, similarly colored when wet; smooth or divided into irregular polygons.

Apothecia: (both species) Apothecia always present, disk-shaped with a thalline margin, minute, less than I mm across.  (Use a hand lens )
      Rinodina marysvillensis: Thalline margin whitish, distinct.
      Rinodina archeae: Thalline margin dark gray, often indistinct.

Soredia:  ( both species )  Lacking.

Isidia:  ( both species )  Lacking.

Comments: Rinodina species resemble those of Lecanora species, but differ in having a blackish thallus.