Pyxine cocoes
≡Lichen cocoes Sw., Nov. Gen. sp. Pl.: 146 (1788).
Description : Thallus closely attached, rosette-forming, 5–15 cm diam. Lobes 0.5–1 mm wide, concave to convex or ±plane, pale grey-white to yellowish white; pseudocyphellae present at margins and as scattered white lines on the lamina; pruina usually present as glistening white patches towards apices of lobes. Soralia developing from marginal and laminal pseudocyphellae, at first punctiform then coalescing into extensive patches; soredia finely granular or farinose, yellowish to grey. Medulla white. Lower surface black. Apothecia not seen.
Chemistry : Cortex K−, UV+ yellow; medulla K−, C−, PD−, UV−; containing lichexanthone and traces of triterpenoids.
N: Northland (Three Kings Is, Helena Bay, Whangarei). On coastal rocks and mangroves (Avicennia marina). Still rather poorly collected in New Zealand. Widely distributed in the tropics (Swinscow & Krog 1975a, 1988; Rogers 1986; Aptroot 1987; Sammy 1988; Kalb 1990, 1994a, 2002; Aptroot 2002e; McCarthy 2003c, 2006; Moberg 2004b).
Pantropical
Illustrations : Rogers (1986: 138, fig. 5; 144, fig. 15, 18); Sammy (1988: 281, fig. 1F); Swinscow & Krog (1988: 264, fig. 129); Brodo et al. (2001: 618, pl. 749).
Pyxine cocoes is characterised by: the corticolous/saxicolous habit; the irregularly orbicular to linear soralia, both laminal and marginal; glistening laminal pruina (Aptroot & Berendsen 1989); and lichexanthone (UV+ gold) in the medulla.
