Ocellularia vizcayensis has a white
thallus that is , meaning it has a loosely structured surface divided into irregular areas. The thallus is covered with a loose , and both the layer containing the (
photosynthetic partner) and the
medulla (the inner layer) have large clusters of
calcium oxalate crystals. The
apothecia (fruiting bodies) are either in the thallus or protruding from thalline warts. They are round, measuring 0.8 to 1.5 mm in diameter, and have a narrow pore only 0.05 to 0.1 mm wide. Surrounding the
ostiole (the apothecial opening), there is a broad zone that is red-brown to purplish brown in color. A (an internal central pillar-like structure in some lichens) is absent. The , or the outer layer of the apothecium, is strongly on the sides, appearing jet-black and is 100 to 200
μm wide. The
hymenium, which is the spore-bearing tissue layer, is clear and tall, ranging from 250 to 400 μm in height, with unbranched . The are large, oblong to in shape, and range from 100 to 300 μm in length and 15 to 30 μm in width. They are colorless, with 15 to 29
septa, and have a violet-blue
staining reaction to
iodine. No
lichen products were detected in the thallus by
thin-layer chromatography.
Ocellularia fuscosporella, found in
New Caledonia, is similar in overall appearance to
O. vizcayensis but has brown ascospores.
Thelotrema monosporum and related species also have superficial resemblance because of their whitish thallus and apothecia with brown rims, but can be distinguished by a differing internal anatomy, a lack of carbonization in the apothecia, the presence of in the hymenium, and brown spores. ==Distribution and habitat==