Daldinia group, spherical

Specimens commonly appear as roughly hemispherical, brown or black outgrowths from wood (usually dead wood). Diameters range from a centimetre or so to over five. The surface is covered with numerous pimples, with a tiny hole (or ostiole) in the centre of each pimple. Below each ostiole there is a small chamber (or perithecium) in which the spores are produced and mature spores exit via the ostiole. Each perithecium could be thought of as a separate fruitbody so the hemispherical outgrowth is composed of numerous perithecia and such a composite structure is called a stroma.

Various species of Daldinia and Annulohypoxylon belong here. In many species of Daldinia a cross-section of the stroma will show you concentric bands, dark ones alternating with light ones.   

Both genera also contain species with non-spherical fruitbodies.

Look-alikes

As a group, this is usually easily recognizable, especially if the fruitbodies are more than say 2 centimetres in diameter. If the fruitbodies are orange-brown, less than a centimetre in diameter and with short, pale green to brownish branching structures on the nearby wood, check Hypoxylon howeianum (https://canberra.naturemapr.org/species/6842).

Reference

Stadler, M. et al, (2014), A polyphasic taxonomy of Daldinia (Xylariaceae), Studies in Mycology, 77,  1–143.

Open access at https://www.studiesinmycology.org/index.php/issue/79-studies-in-mycology-no-77. This is a study of Daldinia worldwide and is technical but includes numerous photos of fruitbodies, showing them both whole and in cross-section.