Thallus: continuous, smooth, immersed in the substrate, whitish photobiont: absent Perithecia: hemispherical, black, immersed in groups of 1-10 below clypeus, c. 0.4-0.7 mm diam. ascomatal wall: black, absent below the hamathecium hamathecium: pseudoparenchymatous, without filaments, inspersed with and dissolving into oil droplets asci: pyriform, c. 50-60 x 15-20 µm, with 8, irregularly arranged ascospores ascospores: hyaline, clavate, 1-septate with a supramedian euseptum, 17-25 x 5-8 µm; walls: not ornamented, without a gelatinous sheath Spot tests: K-, C-, KC-, P-, UV negative Secondary metabolites: none detected. Substrate and ecology: on bark of various woody plants, including Eucalyptus, Machaerocereus, Nicotiana, Pachycereus, Pseudotsuga World distribution: pantropical and extending norhward into southern temperate areas Sonoran distribution: one of the most common pyrenocarps on bark, with numerous records from southern California (including the Channel Islands), Baja California, Baja California Sur and Sinaloa. Notes: A common, pantropical species, which is especially abundant in coastal regions (Harris 1975). It is accepted here in a broad sense, including Tomasellia lactea (Ach.) R.C. Harris, which is only characterized by larger, though overlapping ascospore dimensions. These two taxa were recently classified in Mycoporum (Harris 1995). The occurrence on cacti and barely woody plants like Nicotiana is remarkable.