The lichen forms a very thin, -lacking (ecorticate) crust of whitish- to bluish-grey s, each usually less than 0.1 mm across, scattered or loosely clustered on smooth bark. The
thallus contains
gyrophoric acid, giving a C+ (red) reaction, while
spot tests are otherwise negative.
Apothecia may be absent or abundant. When present they are 0.1–0.5 mm wide, convex to hemispherical, often and proliferating over older ; the margin is lacking and the disc ranges from pale orange-brown to bluish-grey. The is reduced, composed of branched
hyphae; the
hymenium is 50–65 μm high and
stains reddish in
nitric acid.
Asci (usually eight-spored) are 40–55 × 12–15 μm and
amyloid; the oblong-fusiform
ascospores are 7-septate, 27–33 × 4–4.5 μm.
Asexual structures are striking: numerous arbuscular (shrub- or treelike)
pycnidia stand on delicate, often branched stalks 1.4–2.2 mm long, each bearing an inflated, head up to 0.3 mm wide that is thinly hairy and translucent. The pycnidium cavity is packed with filiform conidia, 44–52 × 1–1.2 μm, mostly aseptate (lacking internal partitions, or
septa) but occasionally 1–3-septate. ==Habitat and distribution==