Description
Amandinea species have a crustose thallus ranging from cracked (rimose) to slightly blistered (bullate). The internal white layer (medulla) is iodine-negative (I−), meaning it does not turn blue in the standard iodine test and is therefore non-amyloid. The photosynthetic partner is a chlorococcoid green alga, i.e. with small, spherical cells. Sexual fruiting bodies are apothecia with either a lecanorine margin (rim made of thallus tissue) or a lecideine margin (dark, non-thalline rim). These apothecia may be partly sunk into the thallus ( immersed ) or sit on top of it ( sessile ), with either a broad or narrowed base; the discs are typically black or nearly so. The tissue beneath the spore layer ( hypothecium ) is pale to dark brown, sometimes with olive tones. [8]
Inside the apothecia, the hamathecium is made of paraphyses—microscopic, partitioned threads that run between the spore sacs. These are unbranched or branch only near the tip; the tips are swollen and pigmented, and many bear a dark brown cap. The asci (spore sacs) are club-shaped and of the Lecanora -type; they usually contain eight spores, though four or more than eight may occur. The ascospores are brown and 1-septate (with a single internal cross-wall), sometimes showing a thicker median wall; their surfaces are often finely wrinkled ( rugose ), a feature that generally requires electron microscopy to see reliably. Asexual reproduction is common via pycnidia (tiny flask-like structures) that produce curved, thread-like conidia up to about 30 μm long. Chemical tests rarely detect secondary metabolites in this genus (norstictic acid is uncommon but occurs in a few species), while most species show no substances detectable by thin-layer chromatography. [8]
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