Physcia jackii
Synonyms
P. stellaris sensu Galloway (1985: 394), auct. non (L.) Nyl.
Family
Physciaceae
Flora category
Lichen – Native
Endemic taxon
No
Endemic genus
No
Endemic family
No
Structural class
Lichens - Foliose
Current conservation status
2018 | Not Threatened | Qualifiers: SO
Brief description
Characterised by the corticolous habit; the neat, rosette-forming thallus; abundant, central apothecia; and the K−/K+ yellow medulla; a chemistry comprising atranorin (cortex) and zeorin (medulla).
Distribution
North Island: South Auckland (Thames, Coromandel Peninsula, Raglan, Hamilton), Taranaki (Waipapa, Mt Taranaki), Wellington (Rangitikei, Feilding). South Island: Nelson (Foxhill), Marlborough (Seddon, Hapuku River), Westland (Otira Gorge), Canterbury (Waikari, Banks Peninsula, Mt Somers, Peel Forest, Kelsey’s Bush), Otago (Makarora, Glenorchy, Herbert, Broad Bay Otago Peninsula, Whare Flat, Akatore), Southland (Otautau, Queen’s Park Invercargill, Awarua). Stewart Island: (Traill Park, Butterfield’s Beach Moturau Moana).
Known also from Australia and South Africa).
Habitat
On twigs and bark of trees and shrubs.
Detailed description
Thallus orbicular, rosette-forming to irregularly spreading (encircling twigs), closely attached from margins to centre, 1–2(–7) cm diam. Lobes plane to convex, 0.5–2(–3) mm wide, 3–5(–8) mm long, adjacent to loosely imbricate at apices, densely and complexly imbricate centrally, often also secondarily lobulate or hummocky centrally. Margins entire, shallowly notched, incised or scalloped, not noticeably thickened below. Upper surface pale greenish grey or blue-grey when moist, grey-white to creamish when dry, smooth to minutely granular–crystalline (×10 lens), occasionally minutely maculate centrally (×10 lens), epruinose, esorediate. Lower surface whitish at margins to pale-buff or creamish centrally, smooth, rhizinate. Rhizines sparse to frequent, simple to squarrose-branched (especially at apices), white to pale-tan, 0.4–1 mm long. Apothecia laminal, at centre of thallus, frequent, crowded–congested, sessile, constricted at base, rounded or contorted through mutual pressure, (0.2–)0.5–1(–2) mm diam., thalline exciple persistent, concolorous with thallus, entire, smooth to crenulate–striate, disc plane, matt, dark brown-black, with or without a fine, grey-white, delicately farinose pruina. Epithecium yellow-brown to chestnut-brown, 12.5–18 μm thick. Hymenium colourless, 100–112.5 μm tall. Hypothecium pale yellow-brown, opaque, of densely interwoven hyphae. Ascospores grey-brown, Physcia-type, (20–)22–25(–27.5) × 7.5–10 μm. Pycnidia sparse or absent, to numerous when present, immersed in thallus and visible as black dots. Conidia subcylindrical, 4–5 × 1 μm.
Chemistry: Cortex K+ yellow; medulla K− or + yellow; containing atranorin and zeorin.
Similar taxa
New Zealand material is very uniform chemically and also morphologically. The rather smooth, emaculate upper cortex and the crowded, central apothecia have led to the New Zealand material formerly being identified as P. stellaris. However, true P. stellaris lacks zeorin in the medulla, and no New Zealand collection formerly identified as P. stellaris has atranorin alone in acetone extracts.
Substrate
Corticolous (bark, twigs)
Attribution
Fact sheet prepared by Melissa Hutchison (12 February 2022). Brief description, Distribution, Habitat, Features, and Similar taxa sections copied from Galloway (2007).
References and further reading
Galloway D.J. 1985: Flora of New Zealand: Lichens. Wellington: PD Hasselberg, Government Printer. 662 pp.
Galloway D.J. 2007: Flora of New Zealand: Lichens, including lichen-forming and lichenicolous fungi. 2nd edition. Lincoln, Manaaki Whenua Press. 2261 pp.