Menegazzia pertransita (Stirt.) R.Sant.
* Account prepared by P.W. James (BM).
Parmelia pertransita Stirton, Proc. phil. Soc. Glasg. 10: 294 (1877).
P. amabilis Zahlbr., Denkschr. Akad. Wiss. Wien math.-naturwiss. Kl. 104: 359 (1941).
Holotype: New Zealand. Near Wellington. J. Buchanan. BM!
P. amabilis. Holotype: New Zealand. Otago, Silver Peaks near Dunedin. On Nothofagus solandri var. cliffortioides. January 1934. J.S. Thomson ZA 206, W!
Thallus closely attached, forming regular or irregular, complete or partial rosettes or irregularly encircling twigs, to 20 cm diam., sometimes coalescing to form extensive colonies, corticolous, lignicolous, more rarely saxicolous, muscicolous or terricolous. Lobes numerous, ± radiating at outer edges, medium, very variable, 0.5-3.5 mm wide, distinct at margins, becoming intricately interwoven centrally and there associated with numerous, secondary lobes, terminal lobes irregularly or subdichotomously branched, occasionally ± palmate, contiguous throughout entire length or remaining discrete, often overlapping and becoming ± compressed and distorted centrally, margins sinuous-contorted, entire, occasionally notched, sometimes with very short laterals, not, or sparingly, or rarely notably blackened (in exposed habitats), apices concolorous with thallus or ± suffused-brownish, hollow, lower side of internal cavity with a grey-white, thin, arachnoid tomentum. Upper surface uneven, whitish-grey, pale grey or green-grey, emaculate, ± rugose-uneven, shining, without isidia or soredia. Perforations frequent, median, large, gaping, 0.5-1(-2.0) mm diam., rounded or somewhat irregular through mutual compression of lobes, not elevated, margins depressed or inrolled around perforation. Apothecia numerous, on short inner, often lateral lobes towards centre, usually scattered or becoming clustered, verrucose at first, then markedly turbinate with an elongate or short, stout pedicel, 4-6(-7) mm diam., cupulate, margins thick, becoming thinner at maturity, areolate-striate, exciple coarsely scabrid, disc concave, pale brown, dark brown or red-brown, smooth, shining, epruinose. Epithecium red-brown without granules. Asci 8-spored, cylindrical or ± long-ellipsoid, 100-120 × 40-45 µm. Ascospores ellipsoid, 25-30(-39) × 20-22(-24) µm, wall 2-2.5 µm thick. Pycnidia numerous, clustered on short lateral lobes at centre, rare on marginal lobes, dark red, apices brown. Chemistry: Atranorin (cortex) one or two fatty acids and a UV-, yellow pigment in the medulla (±); medulla K-, C-, Pd-.
N: Wellington (National Park) eastwards to Lake Waikaremoana and south to Cook Strait. S: Marlborough (Pelorus Bridge) east and west of Main Divide to Southland (Longwood Ra.). Lowland and coastal to inland, subalpine, widely distributed and frequently collected from tree bark, more rarely from rocks or mosses on the ground in humid habitats. Probably the most commonly collected non-sorediate species of the genus in New Zealand.
Endemic
M. pertransita is very abundant in Nothofagus forests and is characterised by: large gaping perforations with inrolled edges, pedicellate apothecia with a coarsely scabrid exciple and stalk, 8-spored asci, a non-granular epithecium and the presence of fatty acids in the medulla. Although presently considered endemic to New Zealand its relationship with M. weindorferi from Tasmania needs a closer scrutiny. In some forms of M. pertransita the tomentum of the internal cavity may be ± pigmented pale yellow, however the pigment is not the same as that found in M. foraminulosa and in any case the two species are readily separated by differences in medullary chemistry. M. pertransita is a very variable species, ranging from specimens with small, narrow, radiating lobes to examples with broad, contorted or imbricate lobes. The occurence of perforations is also variable, and in some collections only one or two perforations (usually at the margins of the thallus) may be present in an otherwise well-developed plant. Some specimens from exposed, often subalpine, habitats may be ± suffused with brown pigment.
