Diplotomma canescens
≡Diploicia canescens ssp. australasica Elix & Lumbsch in J.A.Elix, G.A. Jenkins & H.T. Lumbsch, Mycotaxon 33: 463 (1988).
Description : Thallus squamulose to subcrustose, orbicular, adnate, white to grey-white, becoming pale pink or reddish, eventually darker centrally; lobate–effigurate at margins, to 5 cm diam. Lobes radiate–plicate, contiguous, convex, 0.8–1.2 mm wide, ±areolate centrally. Upper surface smooth or with granular, white pruina (×10 lens), particularly towards apices, sorediate. Soralia in scattered, erose patches; soredia white, coarsely granular to farinose. Medulla white, irregularly pigmented yellow, orange or pale red. Lower surface ivory to pale brown, ecorticate. Apothecia not seen.
Chemistry : Cortex K+ yellow; medulla K+ yellow, C−, KC−, Pd+ yellow containing buellolide (major), diploicin (major), canesolide, 3-dechlorodiploicin, secalonic acid A, B, C, atranorin and chloroatranorin.
N: Northland (Three Kings Is), Auckland (Rangitoto I.), South Auckland (Great Mercury I., Motuhora I., Rurima I.), Wellington (Kapiti I.). S: Marlborough (Chetwode Is). On coastal rocks in upper spray zone. Known also from SE Australia and Tasmania (Elix et al. 1988: 463; McCarthy 2003c, 2006).
Australasian
Illustrations : Elix et al. (1988: 465, fig. 7); Lumbsch et al. (2001a: 6); – both as Diploicia canescens ssp. australasica.
Diplotomma canescens ssp. australasica is distinguished from D. canescens s. str. on the basis of chemistry alone (possessing buellolide and canesolide), as morphological characters are identical in both taxa (Elix et al. 1988).
