CALYCIDIUM ^{1 2}

Gintaras Kantvilas ³

Calycidium Stirt., Proc. Philos. Soc. Glasgow 10: 292 (1877).

Type: C. cuneatum Stirton

Thallus foliose, composed of erect, ascending or decumbent, broadly dorsiventrally flattened lobes; upper surface a shade of green or olive-brown; lower surface whitish and wrinkled. Photobiont trebouxioid. Ascomata mazaedia, brown to black-brown, marginal, exposed from an early stage by disintegration of the thalline veil; spore dispersal passive. Ascospores simple, ± globose to irregularly broadly ellipsoid, reddish brown, smooth or minutely verruculose, lacking adhering sterile fragments. Conidiomata unknown. Chemistry: xanthones and sphaerophorin (±).

A genus of two species confined to the cool temperate rainforests of Tasmania, New Zealand and southern South America. Species of Calycidium are readily mistaken for poorly developed species of Bunodophoron, especially B. scrobiculatum or B. macrocarpum, both of which have similarly broadly flattened, sterile branches. The small foliose thallus, marginal, brown mazaedia, and subglobose, reddish brown spores are diagnostic.

Key references: Tibell (1987); Kantvilas (2000); Wedin (2002).

1	Thallus underside UV+ white (containing sphaerophorin); lobe margins incised; apothecia ± subpedicellate	1 C. cuneatum
	Thallus underside UV+ orange (containing xanthones); lobe margins undulate but not markedly incised; apothecia ± sessile	2 C. polycarpum

1 Calycidium cuneatum Stirt.

Proc. Philos. Soc. Glasgow 10: 292 (1877).

Thallus forming irregular patches to c. 15 cm wide; lobes loosely clustered to entangled, 1.5–10 mm wide, to 10(–15) mm long, sparsely divided, with somewhat recurved margins and appearing convex and slightly hooded, broadening from a narrowed base, apically usually distinctly notched and incised; upper surface smooth or occasionally weakly scrobiculate. Apothecia subpedicellate, 0.4–1.5 mm wide, numerous along the upper lobe margins, with a thin but distinct, whitish thalline rim. Ascospores (4.5–)5–5.8–7 × (4–)4.5–5.3–6.5(–7) µm.

Chemistry: sphaerophorin and an unidentified compound; medulla K–, KC–, C–, P–; underside UV+ white.

Known in Tasmania from subalpine elevations in the west and south-west, where it grows on low, horizontally-spreading branches in scrubby rainforest and tall, wet heathland; also known from New Zealand. It is listed as ‘rare’ under the Tasmanian Threatened Species Protection Act 1995.

Hartz Lake, 43°14’S 146°46’E, 950 m, 1999, G. Kantvilas 462/99 (HO); eastern shore of Lake Dove, 41°40’S 145°58’E, 940 m, 2002, G. Kantvilas 555/02 (HO); Lake Cygnus, 43°08’S 146°14’E, 880 m, 2006, G. Kantvilas 489/06 (HO).

2 Calycidium polycarpum (Colenso) Wedin

Lichenologist 34: 67 (2002); —Sphaerophorus polycarpus Colenso, Trans. Proc. N.Z. Inst. 16: 361 (1884).

Thallus forming small tufts; lobes scattered, 1.5–10 mm wide, to 10 mm long, sparsely divided, plane to slightly convex, broadening from a narrowed base, with apices entire to crenulate, not incised; upper surface smooth. Apothecia sessile, 0.4–2 mm wide, occurring along the upper lobe margins, with a very thin thalline rim. Ascospores (4–)5–6.0–7.5(–9) × (4–)4.5–5.4–6(–9) µm.

Chemistry: 3-O-methyl-5,7-dichloronorlichexanthone, 3-O-methyl-2,5,7-trichloronorlichexanthone, plus additional unidentified xanthones; medulla K–, KC–, C–, P–; underside UV+ orange.

Very uncommon in Tasmania and recorded only once, associated with Bunodophoron species and bryophytes on an ancient tree of Nothofagus cunninghamii at the margin of callidendrous rainforest; also known from New Zealand and southern South America. This species is very similar to C. cuneatum but is distinguished by chemical characters and by the sessile apothecia. Like C. cuneatum, it is listed as ‘rare’ under the Tasmanian Threatened Species Protection Act 1995.

Along the road to Corinna, S of Pieman River, 41°40’S 145°05’E, 70 m, 2000, G. Kantvilas 263/00 (HO).

References