Pseudocyphellaria coronata (Müll.Arg.) Malme
Sticta coronata Müll. Arg., Flora 62: 163 (1879).
Lectotype [fide Galloway and James Lichenologist 9: 95 (1977)]: New Zealand. Westland, Greymouth. Comm. F.V. Mueller, G!
Thallus ± orbicular, attached centrally, margins ± free, 5-12(-30) cm diam. Lobes large, rounded, 1.5-5.0 cm wide, margins minutely indented-incised, not sorediate or isidiate. Upper surface bright lettuce-green or glaucous-green or pale yellowish-green when wet, pale greyish-green when dry, cinnamon-brown or suffused purplish on storage, matt to rather waxy, glossy and often tinged brown marginally, uneven, ± deeply faveolate-reticulate, especially towards margins. Medulla yellow. Photobiont green. Lower surface complexly wrinkledverrucose, not or sparingly tomentose, pale yellowish or buff, blackish centrally. Pseudocyphellae yellow to reddish-yellow, to 0.6 mm diam., round to irregular, crowded, papillate, ± bursting at apices. Apothecia small 1-2 mm diam., abundant, contiguous or scattered, often crowded, disc matt, red-brown to blackish, convex to plane, concave when young, margins thin, crenate or denticulate-coronate, irregular, not isidiate, thalline exciple smooth, glossy. Ascospores fusiform, 1-3-septate, colourless, 25-36 × 7-11 µm. Chemistry: Pulvinic dilactone, pulvinic acid, calycin, polyporic acid, and unidentified pigment (red in acetone) 2α,3β,22α-triacetoxystictane, 22α,hydroxystictane-3-one (±), 2α3β-diacetoxystictane-22α-ol, stictane-3β,22α-diol (±), 2αacetoxystictane-3β,22αdiol, 3β-acetoxystictane-2α,22α-diol (±) and stictane-2α,3β,22α-triol (±).
N: S: St: Sn: Ch: A: C: Ant: Throughout, often locally common on twigs or bark in full sunlight or in moderate shade in humid habitats, lowland to subalpine, s.l. to 1500 m.
Australasian
P. coronata is a conspicuous, yellow-medulla species and is distinguished from P. colensoi (to which it seems most closely related) by the broader, rounder lobes which do not have laciniate incised margins, by the characteristically faveolate upper surface, the smaller apothecia with red-brown or black discs with smooth, crenulate but not eroded-isidiate margins, and a distinctive reddishpurple acetone extract. The smooth, glossy thalline exciple distinguishes it from P. degelii and P. flavicans both related species which have also a different morphology and chemistry. Known in 19th century accounts as Sticta orygmaea [see Galloway and James Lichenologist 9: 95 (1977)] it was accurately defined under that name by Babington ( loc. cit., p. 274) as follows "... Thallus a foot wide in a specimen from Colenso, about 3 or 4 inches in the Antarctic specimens, nearly orbicular, running over trees and sticks, glaucous above, becoming darker and greener when moist (usually without any tendency to a rutilant or rufescent hue), very much scrobiculated when in maturity, especially towards the middle, so that the whole thallus appears reticulated and pitted. Here and there the surface (especially after being wetted) has a delicate purple-violet tint, by which character the species may usually be recognized... Difficult as it is to lay down absolute characters, it may be said of this species that its colour is more glaucous, its texture more membranaceous, its lobes less divided, its under side brighter and more bullated, than in S. aurata, D'Urvillei or Colensoi. The apothecia also are darker than in S. Colensoi, and far more numerous and smaller than in any of the three species..."P. coronata is probably the most common, yellow-medulla species of Pseudocyphellaria found in New Zealand and because of its luxuriant growth and special chemistry, it has found widespread popularity as a source of natural dyes, though its use in this connection is to be deprecated. Very often populations are devastated by collectors who imagine that because the lichen is usually well-developed and often also common, it must regenerate quickly. In the interests of conserving New Zealand's unique lichen flora the use of lichens for dyeing must be strongly condemned.
Chemistry of this species is discussed by Chin et al., [ J. chem. Soc. Perkin Trans.: 1437-1446 (1973)].
