Labyrintha implexa
Holotype: New Zealand. South I., Nelson, Cobb Ridge, 1400 m in tussocky subalpine scrub, 10.i.1993, W.M. Malcolm 707 – CHR 470232. Isotypes – ANUC, BM, UPS, W.
Description : Thallus crustose, areolate, irregularly spreading, 1–10(–30) cm wide. Areolae angular, polygonal, 1–3 mm diam., separated by shallow to deep cracks, olivaceous-greyish when wet, the anastomosing pattern of the photobiont resembling a labyrinth or maze (×10 lens), lavender-grey to grey-brown to somewhat rusty brown and ±grey-pruinose when dry (photobiont pattern then obscured). Prothallus black, visible at margins and between areolae. Cephalodia, hummocky-angular, convex-irregular, between areolae, blue-grey to blackish when wet, slightly darker than areolae when dry. Apothecia immersed, occupying up to 80% of the area of areolae, immarginate, plane to subconvex; disc black, epruinose, slightly rugulose-papillate. Hymenium 350–400 μm tall, colourless. Paraphyses branched and anastomosing, septate, 2–3 μm diam., expanding to 5 μm at apices, with a brownish swollen apical cell. Asci cylindrical-clavate 240 × 80 μm. Ascospores 60–70 × 30–35 μm. Pycnidia immersed. Conidia abundant, simple, fusiform 4–6 × 1 μm.
Chemistry : TLC−, all reactions negative.
N: Gisborne (Mt Hikurangi), Taranaki (Mt Taranaki), Hawke's Bay (Mt Kaweka), Wellington (Kaimanawa Mts, Waipakihi Valley, Tongariro National Park, Ruahine Ra.). S: Nelson (Burgoo Stream, Cobb Lake, Mt Arthur Ra., St Arnaud Ra.), Marlborough (Mt Ellis), Westland (Kelly Ra., Fraser Peak, Gorge Plateau, Red Hills), Canterbury (Arthur's Pass, Mt Hutt, Sebastopol), Otago (French Ridge, West Matukituki Valley, Poolburn Reservoir, Old Man Ra., Umbrella Mts, Gem Lake), Southland (Fiordland, Homer Cirque, Henry Saddle, Borland Saddle). St: (Mt Anglem, Table Hill, Mt Allen, granite outcrops at head of Cooks Arm, Port Pegasus, Fraser Peaks, South Cape). C: (Lyall ridge, Mt Honey). Alpine to high-alpine, on siliceous rocks from rock pavements to vertical or overhanging cirque walls (Gem Lake, Umbrella Mts), 960–2000 m, down to 50 m in Port Pegasus. Associating with Aspicilia spp., Bryoria austromontana, Diploschistes spp., Frutidella caesioatra, Immersaria athroocarpa, Lecanora farinacea, L. polytropa, Lecidea spp., Lepraria neglecta, Porpidia spp., Protoparmelia badia, Pseudephebe pubescens, Rhizocarpon spp., Umbilicaria spp., Usnea acromelana, U. ciliata, U. torulosa, Xanthoria elegans and Xanthoparmelia mougeotina.
Endemic
Illustrations : Malcolm (1995: 276, fig. 1; 277, fig. 2); Malcolm et al. (1995a: 244, figs 1–4; 245, fig. 5; 246, fig. 6); Malcolm & Galloway (1997: 99, 162, 145, 186); Malcolm & Malcolm (2000: 42, 43, 54; 2001: 65).
Labyrintha implexa is distinguished from closely related genera (such as Amygdalaria, Notolecidea, Poeltidia, Porpidia), and is characterised by: the saxicolous habit; cephalodia containing Gloeocapsa; immersed, aspicilioid apothecia; large, simple ascospores (60–70 × 30–35 μm), halonate when young and dark-pigmented when mature; Porpidia -type asci; fusiform conidia; no cortex; no thallus chemistry; densely packed anticlinal hyphae; and a thallus anatomy in which the photobiont is arranged in anastomosing vertical sheets. In the field it may be confused with species of Placopsis that have immersed apothecia (e.g. Placopsis durietziorum), but it has lecideine apothecia (without photobiont cells in the exciple), a differing arrangement of the primary photobiont, and differently structured cephalodia. It was recorded from Phipps Peak, Arthur's Pass as Lecanidium thomsonianum (Zahlbr.) C.W.Dodge, nom. inval. (Fineran & Dodge 1970: 403) [Fineran 2275, iii.1966 – CANU!], and as Pertusaria perrimosa Nyl. (Fineran & Dodge 1970: 405)[Fineran 2201, iii.1966 – CANU!].
