Umbilicaria leiocarpa DC.
Thallus 2-8 cm diam., mono- or polyphyllous, orbicular with irregular, fragile margins, usually deeply incised and with few, scattered pin holes. Upper surface uneven to plicate, elevated over umbo, moderately wrinkled-ribbed becoming slightly rimose-areolate at margins, areolae slightly raised, surface dull, buff to dark brownish-black with a faint, pale pruina centrally. Lower surface somewhat folded and indented, smooth to subpapillate, sooty, scurfy, paler or greyish at margins, areolate, rhizines absent. Apothecia 1.5-2 mm diam., scattered, marginal, free, stipitate, black, plane, without gyrae or sterile fissures. Hymenium to 50 µm tall. Paraphyses simple, septate, 2.4 µm thick becoming brown, apices globose, 4.2 µm thick. Hypothecium 100 µm thick, irregular, black. Ascospores simple, colourless 12-14 × 5 µm.
S: Nelson (Cobb Ridge on serpentine, J.K. Bartlett), Canterbury (Torlesse Ra.). On alpine rocks, rare.
Bipolar
