Puttea caesia
Thallus indistinct, consisting of a thin layer of delicate hyphae and small algal cells, mostly immersed in wood.
Anamorph: not known.
Teleomorph: ascomata apothecia, minute (0.1-0.2 mm diam.), whitish, roundish, convex, usually with a narrow dark rim due to the pigmented excipular cell apices. Outer wall of parallel, gelatinized hyphae with narrow lumina running perpendicularly to the outer surface that are thickened (to ca 4 µm diam.) and often brown-pigmented at the apex, the inner tissues of gelatinized interwoven hyphae. Both hymenium and flanks covered with a narrow gelatinous layer topped with crystals, these dissolving totally in most reagents. Hypothecium colourless. Interascal tissue of branched and anastomosing hyaline paraphyses, of similar length to the asci. Asci clavate, thick-walled, faintly amyloid (MLZ), strongly hemiamyloid (IKI) with inner blue tholus and outer brownish reaction, arising from croziers, 8-spored. With KOH-pretreatment the tholus can be seen to be penetrated by a canal surrounded by darker blue walls in IKI. Ascospores 5 –8 × 1.5–2.5 μm, hyaline, thin-walled, smooth, ellipsoidal to subfusiform, aseptate, with prominent vacuolar remains in most reagents.
Not formally assessed. Only one confirmed GB&I record, but the species is very inconspicuous and liable to be overlooked.
Puttia margaritella (not yet recorded for GB&I but likely to occur here) has slightly wider ascospores (5.5–7.5 × 2.5 –3 µm), and apothecia without a dark rim. It is an apparent parasite of the widespread corticolous leafy liverwort Ptilidium pulcherrimum.
In GB&I, recorded from rotting wood of a Picea sitchensis stump, in a felled plantation.
Reported from VC97 Westerness, with a possible historical record from VC92 S Aberdeenshire.