Thysanothecium scutellatum (Fr.) D.J.Galloway
Cladonia ?scutellata Fr. in Lehmann, Pl. Preiss. 2: 141 (1846) "1846-1847".
Baeomyces hyalinus Taylor, Hook. Lond. J. Bot. 6: 187 (1847).
Holotype: West Australia, Sine loco. Ad caudicem Macrozamiae Preisii. Herb. Preiss, No. 2696, UPS!
Primary thallus squamulose, or ± nodular-papiliate, squamules ± dorsiventral, scattered to ± densely packed, imbricate, forming a spreading, diffract- areolate crust, minute, 0.05-0.5(-1.0) mm diam., margins crenate, becoming lobulate, convex and ± closely attached to substrate, to ascending, ± imbricate, whitish or pale greenish to greenish-yellow above, tinged brownish at apices, white below, often clothing base of pseudopodetia to 5 mm, on charred or decorticated wood. Pseudopodetia arising from margins or apices of primary squamules, at first simple, terete and uniformly corticate, at maturity fissured, grooved, ± canaliculate or partly hollow, formed of horny, cartilaginous nerve- like strands between which corticate granules and medullary hyphae are exposed, 1-2 mm wide at base, flaring to 2-6 mm wide at apices, 0.1-10(-15) mm tall. Cortex yellowish-green to brownish, distinctly grooved-striate, discontinuous, cartilaginous strands corticate, glossy, spaces between filled with corticate granules and medullary hyphae. Apothecia terminal often also subterminal on secondary branches, disc ± plane, rotund at first, becoming irregular- undulate, fan-shaped or deeply crenulate-lacerate, margins entire at first, becoming sinuous, crenate, persistent, distinctly raised, concolorous with thallus or paler, surface of disc smooth or very minutely scabrid, pale yellowish- green to pinkish-brown, not or rarely minutely white-pruinose. Ascospores ellipsoid, straight or slightly curved, 5-8 × 3 µm. Pycnidia marginal on primary thallus, black, cylindrical to bottle-shaped, with an apical gaping ostiole 0.05-0.08 mm wide. Conidia not seen. Chemistry: Cortex and medulla K-, C-, KC-, Pd-. Divaricatic and usnic acids.
N: North Auckland (Radar Bush near Pandora, to Waitakere Ra. and Coromandel Peninsula), South Auckland (near Thames to Taupo). S: Nelson (Lake Rotoroa), Westland (near Ross), on charred wood mainly (Dacrydium kirkii, Dacrycarpus dacrydioides, Leptospermum scoparium, Agathis australis) rarely on decorticated wood, coastal and inland, s.l. to 300 m, an easily overlooked species.
Western Pacific
T. scutellatum has a mainly northern North I., distribution but occurs in South I., in Nelson and Westland habitats following closely the distribution of species of Erioderma, and species of Pannaria (especially P. fulvescens). The characteristically fissured cortex with corticate granules protruding from the cartilaginous network of nerve-like strands, the marginate apothecia, and the morphology of the primary thallus, distinguishes it from the related T. hookeri, which is a terricolous species and is not known from wood, either charred or decorticated. Its chemistry is also distinct.
