Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.

Apothecia: dispersed on the host thallus, immersed to superficial, black, (100-)200-300 µm in diam. margin: in opened ascomata 75-100 µm thick, sometimes with deep fissures; ascomatal pore: 50-75 µm in diam. exciple: laterally hyaline to reddish or violet brown in the inner part, dark gray to brownish gray in the outer part, K+ bright aeruginose green, N+ dark reddish brown, 10-40 µm thick, basally the same color and reactions, but just below the subhymenium reddish brown, K+ pale purple or violet, N-, 15-20 µm thick; excipular hairs: dark grayish brown, K+ bright aeruginose green, N+ dark reddish brown, with irregular, pigmented ring-like structures, 30-48 x 2.5-3 µm epihymenium: hyaline hymenium: hyaline, 30-60 µm tall asci: cylindrical to elongate clavate, 43-50 x 5-8 µm ascospores: hyaline, 0(-1)-septate, narrowly ellipsoid, (8)9-12(-13) x 2.5-3 µm. Host: on the thallus of Pyrrhospora cf. quernea World distribution: coastal regions of western North America Sonoran distribution: California (Cambria and San Miguel Islands). Notes: Skyttea tavaresiae is mainly characterized by its unusual dark grayish brown exciple, which is K+ bright aeruginose green and N+ dark reddish brown (basally with an additional, reddish brown, K+ purplish or violet pigment). It should not be confused with Skyttea pertusariicola, a species with the same pigments (see under that species for differences).