Bactrospora arthonioides
Description : Thallus crustose, effuse cobwebby, to ±areolate, whitish, appearing pale orange-yellow near cracks (Trentepohlia growing out from inner layers), or sometimes irregularly covered with patches of green aerial algae and appearing greenish; forming irregular patches 2–10(15) cm diam., not delimited by a line of prothallus, rather ragged-effuse at margins. Photobiont Trentepohlia (fresh thalli orange-yellow when scratched). Apothecia black, matt, epruinose, widely scattered to numerous, rounded to somewhat irregular, 0.1–0.3(–0.4) mm diam., initially semi-immersed, soon becoming erumpent, adnate, not constricted at base, immarginate, disc ±convex. Exciple very thin, dark-brown, open below subhymenium, 15–25 μm thick at top, 5–12 μm thick at base, I−, IKI−. Hymenium 75–80(–100) μm tall, colourless to pale brownish, I+ reddish. Subhymenium pale-brown, 70–100 μm thick, I+ pale-blue. Apical cells of paraphysoids, somewhat thickened, dark-brown, forming a reticulate pseudoepithecium. Asci cylindrical with a long stalk, 62–80 × 10–15 m. Ascospores Patellarioides -type but with short cells, 10–15-septate, narrowing at one end rounded at other, 45–60 × 3–4 μm.
S: Otago (Mt Cargill). On rimu scales (Dacrydium cupressinum), forming spreading patches and mosaics with other encrusting lichens such as B. metabola, Chiodecton colensoi and species of Pertusaria and Thelotrema. Known also from Tasmania (Egea & Torrente 1993a: 221; Kantvilas 2004j: 186).
Australasian
Illustrations : Egea & Torrente (1993a: 220, fig. 3C–F); Kantvilas (2004j: 186, fig. 1A, B).
Bactrospora arthonioides is distinguished by: the corticolous habit; and the 10–15-septate Patellarioide s-type ascospores that are rounded at one end and narrowed at the other.
