INGVARIELLA ¹

Gintaras Kantvilas ²

Ingvariella Guderley & Lumbsch, in R. Guderley, H.T. Lumbsch & G.B. Feige, Nova Hedwigia 64: 152 (1997).

Type: I. bispora (Bagl.) Guderley & Lumbsch

Thallus crustose, with a pseudocortex of rather amorphous hyphae. Photobiont trebouxioid, with ± globose cells 7–15 µm diam. Ascomata apothecia, urceolate, sunken in the thallus, lacking a proper exciple but with a thin margin derived from degenerated, carbonised hymenial material, typically enveloped with thalline tissue; periphyses absent. Disc grey-black, deeply concave, widely exposed from the outset. Hypothecium mostly hyaline. Hymenium hyaline, I+ slowly yellowish brown, KI+ deep blue. Asci cylindrical, 2(–4)-spored, with a thickened tholus, KI– or KI+ very weakly blue, and an intensely KI+ blue outer wall and cap. Paraphyses simple, slender, straight, 1–2 mm thick, separating in K, non-capitate. Ascospores muriform, broadly ellipsoid to oblong, non-amyloid, at first hyaline, soon becoming grey and then brown, non-halonate, thin-walled. Conidiomata not known. Chemistry: nil.

A monotypic genus widely distributed in drier, temperate parts of the world, including the Australian mainland. Due to a superficial resemblance and a suite of shared characters such as the saxicolous habit, trebouxioid photobiont, urceolate apothecia, straight, simple paraphyses, and muriform ascospores, Ingvariella was considered in the past to be related to Diploschistes (Graphidaceae). However, its position there was always tentative and with the support of molecular data and a re-evaluation of several key anatomical features, notably the absence of periphyses, structure of the ascomatal wall, and the reaction of the asci in iodine (Fernández-Brime et al. 2011), it has been transferred to the Stictidaceae, with relationships to Absconditella, Conotremopsis and Cryptodiscus, corticolous or muscicolous genera with minute, gyalectoid apothecia.

Key references: Guderley et al. (1997); Mangold et al. (2009); Fernandez-Brime et al. (2011).

1 Ingvariella bispora (Bagl.) Guderley & Lumbsch

In R. Guderley, H.T. Lumbsch & G.B. Feige, Nova Hedwigia 64: 152 (1997); —Urceolaria bispora Bagl., Nuovo Gior. Bot. Ital. 3: 246 (1871); Diploschistes bisporus (Bagl.) Steiner, Sitzungsber. Kaiserl. Akad. Wiss., Wien, Math.-Naturwiss. Cl., Abt. 1, 102: 155 (1893).

Thallus reddish brown to bronze, rimose-areolate, smooth to rather unevenly lumpy, to c. 500 µm thick, forming undelimited patches to c. 50 mm wide, interspersed with other lichens. Apothecia 0.3–1 mm diam., scattered or crowded together; margin in section opaque brown, 30–100 µm thick. Hypothecium 30–90 µm thick. Hymenium 70–110 µm thick, overlain by a brownish grey, granular epithecium unchanged in K; asci 2-spored, 68–90 × 22–30 µm. Ascospores densely muriform with up to 8–13 transverse and 3–5 longitudinal septa, 30–37.5–48(–56) × (14–)15–18.4–24.5(–29) µm.

Occasional on exposed rocks, mainly in lowland, low-rainfall areas but also sometimes extending to alpine elevations. The deeply urceolate apothecia, sunken in the bronze, crustose thallus, are diagnostic.

Above Black Gully Creek, 1 km NE of Hamilton, 42°33’S 146°51’E, 140 m, 1999, G. Kantvilas 252/99 (HO); Bisdee Tier, 42°26’S 147°17’E, 640 m, 2009, G. Kantvilas 133/09 (HO); Mt Montagu summit, 42°55’S 147°10’E, 1060 m, 2016, G. Kantvilas 28/16 (HO).

References