Globosphaeria jamesii
Description : Thallus immersed, of pale brownish hyphae, uneven in thickness, 2–3 μm wide, enveloping algal cells within host. Perithecia, subglobose, superficial, immersed only at base which is constricted, (0.2–)0.25–0.3 mm diam., blackish brown but black around ostiole. Ostiole not or scarcely papillate, the pore c. 30 μm diam.; perithecial wall up to c. 50 μm thick, dark reddish brown in squash preparations, of branching hyphae 2–3.5 μm thick arranged parallel to outer surface (textura intricata) on the surface, mainly composed of polyhedral pseudoparenchymatous cells 6–8 μm diam. (textura angularis). Centrum I−. Paraphyses sparse, simple or occasionally branched at base, filiform, regularly septate, 2–3.5 μm wide. Asci 80–90 × 8–11 μm, including stalk that may reach 30 μm long. Ascospores globose, 8–10 μm diam., but becoming compacted in twos and threes and then somewhat angular prior to discharge, walls up to 2 μm thick, with a single, plane germ pore, c. 0.5 μm diam.
S:? Known from Tasmania (Hawksworth 1990b), and recently reported from the west coast of North America (Diederich 2003: 55).
?Circum-Pacific
Host : On thalli of Normandina pulchella (Borrer) Nyl. The host is not discoloured in any way, suggesting the species is commensalistic and not parasitic. Only two other lichenicolous fungi are known from this host. The widely distributed Lauderlindsaya borreri (Tul.) J.C.David & D.Hawksw., a member of the Verrucariales, produces ellipsoidal–fusiform, mainly 7-septate ascospores (David & Hawksworth 1989). Capronia normandiae R.Sant & D.Hawksw. densely setose perithecia and ellipsoidal to broadly fusiform, muriform, pale olivaceous brown ascospores (13–)15–21(–23) × 7.5–9 μm (Hawksworth 1990a).
Illustrations : Hawksworth (1990b: 304, fig. 1A–F).
* Globosphaeria jamesii is characterised by: the lichenicolous habit (on thalli of Normandina pulchella); brownish black, superficial perithecia; and thick-walled, globose, colourless ascospores, 8–10 μm diam.
