Caloplaca lecapustulata is characterised by a crustose (crust-like), , and slightly shiny
thallus (the main body of the lichen) that is grey in colour. It features (small, distinct areas) that can appear (blistered) to somewhat flattened or slightly folded, ranging from round to angular shapes, each about 0.2 to 1.0 mm in diameter, situated on a black base layer known as the . The thickness of the thallus is approximately 100 to 220
μm, with a loosely structured
medulla (internal layer) and a cortex (outer layer) that is (composed of tightly packed cells) and contains tiny crystals of a substance called
atranorin, measuring about 10 to 18 μm thick. The lichen houses algae, with cells measuring about 6 to 11 μm in diameter. This species does not produce vegetative
propagules (asexual reproductive structures). The
apothecia (fruiting bodies) of
Caloplaca lecapustulata are numerous, spread out, and (attached directly by their base), with a concave, chocolate brown, glossy that ranges from 0.4 to 1.0 mm in diameter and 0.3 to 0.7 mm in height. The margins are grey, glossy, and incurved with some incisions, significantly elevated above the disc and about 0.2 mm wide. Similar to the thallus, the cortex around the margin of the apothecium is filled with atranorin crystals, and the medulla in this area contains algae. The
hymenium (spore-bearing layer) is about 75 to 95 μm high, with a colourless (outer layer of the apothecium), a clear (base layer below the hymenium) measuring about 50 to 75 μm high, and a brown (top layer of the hymenium) about 7 to 12 μm high. The
paraphyses (filamentous structures within the hymenium) are sparingly branched at the tips and widen towards the end. The , numbering eight per
ascus (spore-producing sac), are
hyaline (transparent),
ellipsoid in shape, and measure 10.0 to 12.5) by 5.0 to 5.5 μm. They are about twice as long as they are wide, with a
septum (dividing partition) that is about 5.0 to 5.5 μm thick, occupying roughly half the length of the ascospore.
Pycnidia (asexual reproductive structures that produce
pycnidiospores) have not been observed to occur in this species. ==Habitat and distribution==