Verrucaria maura Wahlenb.
Thallus black, rather thin, gelatinous, distinguished by regular network of fine black cracks (×10 lens). Perithecia immersed in low elevations with only ostioles visible, more prominent when dry. Ascospores ellipsoid, 12-17 × 7-8 µm.
N: Three Kings Is to Wellington. S: Nelson to Southland. St: A: C: Very widely distributed on marine rocks at, and just below, high water mark where it can form extensive patches, the black thallus resembling splashes of tar. Often in ± continuous belts or zones.
Cosmopolitan