Peltigera didactyla
Family
Peltigeraceae
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 terricolous/muscicolous habit; the presence of laminal, orbicular soralia (frequently reacting C+ pink), and a ±tomentose upper surface on small, cochleate lobes that are also often attacked by white to orange or pinkish lichenicolous fungi. The juvenile, sorediate phase is eventually superseded by a fertile, non-sorediate phase.
Distribution
North Island: South Auckland (Kawhia, Napier–Taupo Road). South Island: Nelson (St Arnaud Range, Travers Range, Reefton), Canterbury (Lake Tekapo, Mt Sebastopol, Rangitata River mouth), Otago (Matukituki Valley, Pigeon Island Lake Wakatipu, Dunstan Mountains, Mt Benger, Gem Lake, Lake Onslow, Deep Stream, Taieri Mouth), Southland (Argyle Burn, Oreti Plains, Doubtful Sound, Greenhills).
A widespread, cosmopolitan lichen known from North America, Great Britain, Scandinavia, Greenland, Svalbard, Europe, Asia, South America, Africa, Australia, South Georgia, South Orkney Islands, South Sheltland Islands, and Antarctica.
Habitat
On damp, often bare soil or among mosses, or in subalpine turf, commonly at roadside verges among moss and pebbles at edge of bitumen, or at edges of gravel paths or in weedy, mossy banks in gardens, s.l. to 1500 m. It is normally a rather ephemeral, short-lived, fast-growing, pioneer species in disturbed habitats (e.g. clay banks, washouts and slips, alongside roads), commonly attacked by lichenicolous fungi such as the orange-pink Illsporium carneum, and by Corticifraga fuckelii and C. peltigerae.
Detailed description
Thallus orbicular, small, often cochleate. 0.5–2(–3) cm diam. Lobes 1–2 (rarely 3–5) cm long, 0.5–1(–2) cm wide, plane to ascending, 100–200 μm thick. Margins entire, often incurled. Upper surface coriaceous, dark slate blue-black, suffused dark red-brown when wet, brownish grey or pale greyish green, suffused red-brown when dry, tomentose; tomentum most apparent in fertile, non-sorediate lobes, thinly arachnoid, continuous or discontinuous in scattered, rather tattered patches at margins and centrally; sorediate. Soralia marginal and laminal in rounded to oblong, erose spots or patches, disappearing in older, usually fertile specimens; soredia coarse, granular, grey-blue to red-brown. Lower surface pale whitish or brownish pink. Veins distinct, raised, 0.5–1.0 mm wide, whitish to pale-buff, darkening centrally, interstitial spaces conspicuous, white, fibrous. Rhizines simple at first, soon becoming fasciculate, ±penicillate at maturity, to 2.5 mm long, rather sparse at margins, common at centre. Apothecia on ascending, revolute lobes, 2–4 mm diam., rounded to irregular-elongate, disc red-brown to brown-black, matt, epruinose, margins pale-buff, crenulate–corrugate. Ascospores elongate–fusiform, 5–7-septate, 55–70 × 3–4 μm.
Chemistry: Medulla TLC−, all reactions negative; soredia C± pink-red (fading rapidly) containing gyrophoric acid
Specimens from high-alpine habitats (e.g. Dunstan Mountains) have very thick, ±upright lobes and develop a thick, white, fibrous tomentum at the margins (often ±loosely attached and sloughing off), and copious white, penicillate rhizines below; the laminal soralia are often poorly developed. A particularly robust form from Doubtful Sound, Fiordland [Murray 3946 and identified by James Murray as P. canica var. canica] has broad, ±rounded lobes (1–2 cm broad and 3–5 cm long) that are uniformly tomentose and with ±scabrid–areolate patches at margins and occasionally centrally. It has scattered submarginal (rarely central) soralia, containing coarse, granular, blue-grey soredia (C+ pink), and characteristic flocculent–entangled, short rhizines associated with narrow, raised veins on the lower surface, the rhizines often projecting as a fringe at lobe margins. The Fiordland and high-alpine specimens, although much larger than the typical, small, cochleate forms from disturbed habitats in rural and urban areas, are here maintained in P. didactyla pending further study of the variation of this species in New Zealand.
Similar taxa
It is distinguished from P. ulcerata by its thinner, ±tomentose lobes.
Substrate
Terricolous, muscicolous
Attribution
Fact sheet prepared by Marley Ford (29 August 2021). Brief description, Distribution, Habitat, and sections copied and Features adapted from Galloway (2007).
References and further reading
Galloway D.J. 2007: Flora of New Zealand: Lichens, including lichen-forming and lichenicolous fungi. 2nd edition. Lincoln, Manaaki Whenua Press. 2261 pp.