FRUTIDELLA ^{1 2}

Gintaras Kantvilas ³

Frutidella Kalb, Hoppea 55: 582 (1994).

Type: F. caesioatra (Schaer.) Kalb

Thallus crustose to granular-papillate, ecorticate, with or without soredia. Photobiont a unicellular green alga with globose cells 7–12 µm wide. Ascomata apothecia, biatorine. Disc grey to blackish, commonly faintly bluish grey-pruinose. Proper exciple ± annular, becoming reflexed and ± excluded, in section not carbonised and composed of conglutinated, radiating, sparsely branched and anastomosed hyphae 1.5–2 µm thick. Hypothecium hyaline or pigmented. Hymenium hyaline, amyloid but with the reaction confined to the asci, not inspersed, overlain by a blue-green, N+ crimson epithecium, remaining ± coherent in K. Paraphyses rather robust and straight, simple to sparsely branched and anastomosed, generally with the apices non-capitate and unpigmented. Asci clavate, 8-spored, approximating the Lecanora- or Biatora-types: with a well-developed, amyloid tholus, penetrated entirely or almost so by a broadly conical to barrel-shaped, non-amyloid masse axiale, sometimes with a darker staining, amyloid edge, and with a short, conical ocular chamber. Ascospores simple, hyaline, non-halonate, ellipsoid, usually with a distinct wall. Conidiomata pycnidia, immersed. Conidia filiform, straight. Chemistry: sphaerophorin or xanthones characterise the two known species.

A genus of two species found over saxicolous mosses (F. caesioatra) or on bark [F. furfuracea (Anzi) M. Westb. & M. Svenss.] in cold environments.

Key references: Kalb (1994); Gilbert (2009); Davydov et al. (2021).

1 Frutidella caesioatra (Schaer.) Kalb

Hoppea 55: 582 (1994); —Lecidea caesioatra Schaer., Naturw. Anzeiger Allgem. Schweizer. Gesellsch. Naturwiss. 2: 10 (1818).

Thallus crustose, granular-papillate to bullate, pale beige-grey, cream-grey to brownish, loosely attached and forming spreading, rather discontinuous colonies to 10 cm wide; individual granules and papillae 0.1–0.3 mm wide, apically rounded or flattened, densely packed together, rarely fused. Apothecia 0.4–1.2 mm wide, subglobose to hemispherical, typically nestled deeply amongst the thallus granules; disc at first plane to undulate, soon becoming convex, occasionally rather tuberculate, grey-black to black, usually with a faint bluish grey pruina; proper exciple soon excluded, in section 50–65 µm thick, hyaline to pale yellowish. Hypothecium 40–100 µm thick, hyaline to pale yellowish in the upper part, yellow-brown, K+ intensifying golden-yellow below, poorly differentiated from and subtended by a sometimes massive, yellow-brown subhypothecium. Hymenium 55–75 µm thick, diffusely bluish green, overlain by a deep blue-green, 10–15 µm thick epithecium inspersed with crystals that do not dissolve in K; paraphyses 2–3 µm thick, occasionally with the apices expanded slightly to 4 µm by a thin, external, gelatinous cap; asci 50–60 × 17–20 µm. Ascospores (11–)12–15.4–20(–21) × (4.5–)5–6.6–8.5(–9) µm; wall c. 0.5 µm thick. Conidia not found, reported (Gilbert 2009) as 15–25 × 0.7–1 µm.

Chemistry: sphaerophorin; thallus K–, KC–, C–, P–, UV± weaky whitish.

A bipolar species, found in alpine or polar environments worldwide and recorded in Australasia from the high mountains of south-eastern mainland Australia and from New Zealand. It is rare in Tasmania and known only from high dolerite peaks, especially on the Ben Lomond Plateau, where it overgrows mosses on exposed, wind-swept boulders. It is usually easily recognised by its greyish, papillate thallus and thinly pruinose apothecia; the presence of sphaerophorin is diagnostic. The same apothecial pigmentation is seen in species of Lecidella and Carbonea. The papillate-bullate thallus of Frutidella can resemble Schaereria bullata, which grows in the same habitats but which differs by having a dark brown thallus, persistently marginate, epruinose, black apothecia, Schaereria-type asci and globose ascospores.

Plateau of Mt Olympus, 42°02’S 146°06’E, 1430 m, 2004, G. Kantvilas 23/04 (HO); Snowdrift Tarns, 42°55’S 146°39’E, 1270 m, 2009, G. Kantvilas 435/09 (HO); Ben Lomond, c. 750 m SE of Giblin Peak, 41°32’S 147°40’E, 2022, G. Kantvilas 289/22 (HO).

References