Dichoporis ziziphi

Thallus pale brown, continuous or slightly cracked, thin, mostly immersed in bark. Ascomata, not seen in British material, black, (0.2-)0.3-0.4(-0.5) mm diam.. Ascospores 1-septate, separating into part-spores at ascus dehiscence or before, part-spores 18-28 x 3.5-5.5 μm. Macropycnidia semiglobose, 0.15 – 0.2 mm diam., macroconidia, 1-septate, (8–) 9 – 10 x 3 – 3.5µm μm, each cell with a large, persistent oil droplet, at each end with a poorly visible gelatinous appendage 2.8-3.3 x 3-4 μm; conidiogenous cells short > 8 μm long;  micropycnidia like the macropycnidia but 0.1 – 1.5mm diam.; microconidia fusiform to subfusiform, 2.5-5 x 1-2 μm.

At first sight in the field, this lichen resembles Dichoporis taylorii, but that has a dark brown thallus with the macropycnidia smaller and frequently with perithecia, which are the same size as the macropycnidia of D. ziziphi. The macroconidia of D. taylorii are also longer, typically 13.5–17 x 2.5–3µm. D. phaea has a greenish thallus and shorter macropycnidia (7–8.5 × 2–2.2 µm) on long conidiogeneous cells (10–20 µm long). In addition, there is an undescribed Dichoporis species, which is also known from the New Forest, but is more frequent. This has a paler thallus, more irregular, often conjoined, macropycnidia, with conidia on long conidiogeneous cells (10–20 µm) and the conidia similar in size but a bit longer and less wide (10–12.5 (–14) x 2.5–3µm).