Dufourea incavata
Synonyms
Jackelixia incavata, Oxneria incavata, Physcia incavata, Xanthoria incavata, Xanthoria parietina var. incavata
Family
Teloschistaceae
Flora category
Lichen – Native
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Structural class
Lichens - Foliose
Current conservation status
2018 | Data Deficient
Brief description
Characterised by the corticolous habit; neat, rosette-forming thalli 2–7 cm diam., with entire, rounded margins conspicuously thickened and inrolled below and there furnished with 1–2 discontinuous rows of short, whitish rhizines, with larger more scattered whitish rhizines elsewhere on the lower surface. The upper surface is pale-yellowish to yellow-orange, matt and coriaceous. Apothecia are ±central, rounded, subpedicellate with occasional whitish rhizines developing on the thalline exciple below the disc. The proper exciple is prosoplectenchymatous, a type found also in Xanthomendoza (q.v.) and in the recently described Xanthoria bonae-spei (Kodratyuk et al. 2004a: 354–355).
Distribution
South Island: Marlborough (Molesworth), Canterbury (Ashley Gorge, Selwyn Gorge). Recently observed on Banks Peninsula (Knight 2019, Hutchison 2019).
Habitat
Dufourea incavata is a corticolous species in the Xanthoria parietina-group, so far known only from bark of Acer pseudoplatanus*, Hoheria and Populus nigra* where it associates with Haematomma babingtonii, Hyperphyscia adglutinata, H. plinthiza, Phaeophyscia hispidula, P. orbicularis, Physcia adscendens, P. jackii, Punctelia subrudecta and Teloschistes velifer. It is still extremely poorly collected and understood in New Zealand and its ecological requirements are not fully understood (Kondratyuk & Galloway 1996).
Detailed description
Thallus rounded, in neat rosettes 2–7 cm diam., closely attached centrally and at margins, corticolous. Lobes 8–20(–35) mm long and 3–5 mm wide, moderately thick, occasionally discrete from margins to centre, generally ±imbricate, margins rounded, entire, conspicuously thickened below. Upper surface plane to undulate, shallowly ridged or pitted, matt, coriaceous, pale yellow-white or yellow at margins, darkening centrally. Lower surface white, smooth, with 1–2 rows of short (0.1 mm tall), tufted discontinuous groups of white rhizines along lower side of margins, elsewhere with scattered white anchoring rhizines 0.5–1 mm long. Apothecia sessile to subpedicellate, clustered centrally, rounded to irregular through mutual pressure, (0.5–)1–2(–3) mm diam., disc matt, orange, plane to subconvex or shallowly undulate; thalline exciple concolorous with thallus, thick, persistent, entire, occasionally with short, tufted, whitish rhizines below; proper exciple pseudoproso-plectenchymatous. Asci 57–65 × 16–18 μm. Ascospores 14–5–19 × 7.2–10 μm. Pycnidia scattered or in small groups, submarginal and laminal, slightly raised, orange, with a darker apical pore.
Chemistry: K+ purple; containing parietin.
Similar taxa
From the few specimens examined, Dufourea incavata is a rather constant species similar to Xanthoria parietina (particularly shaded specimens), but differing from it in the mode of attachment to the substratum (rhizines at lobe margins and scattered elsewhere on the lower surface, rather than scattered hapters as in X. parietina); the thickening and inrolling of the lower surface of the lobe margins; the generally smaller apothecia with occasional excipular rhizines, and the thicker, more coriaceous lobes. Additional collections are necessary to establish unequivocally the limits of variation in this species. It is possible that D. incavata might be better accommodated in Xanthomendoza (q.v.), though a definite opinion on its true status has not yet been settled, and recently Kondratyuk & Kärnefelt (2003) transferred it to the new genus Oxneria, though this is still somewhat in doubt.
Substrate
Corticolous
Attribution
Fact sheet prepared by Melissa Hutchison (26 June 2021). Information in the Brief description, Distribution, Habitat, Features and Similar taxa sections copied from Galloway (1985, 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.
Hutchison M.A. 2019: iNaturalistNZ observation of Dufourea incavata. https://inaturalist.nz/observations/35404071
Knight A. 2019: iNaturalistNZ observation of Dufourea incavata. https://inaturalist.nz/observations/24545888
Kondratyuk S.Y. and Galloway D.J. 1996: Notes on Xanthoria Th.Fr. 1. The identity of Xanthoria incavata (Stirton) Zahlbruckner. Lichenologist 28(2): 189–193.
Kondratyuk S.Y. and Kärnefelt I. 2003: Revision of three natural groups of xanthorioid lichens (Teloschistaceae, Ascomycota). Ukrayins’kyi Botanichnyi Zhurnal 60: 427–437.
Kondratyuk S.Y., Kärnefelt I, Søchting U. and Arup U. 2004a: New species of Xanthoria (Teloschistaceae) from Southern Africa. Bibliotheca Lichenologica 88: 349–362.