A cousin of Aulopora is Aulocystis. This is easily distinguished from the former by the fact that colonies don't encrust shells. Rather they grew as single branching colonies or as dense colonial clusters.
Here are some of those cluster type Aulocystis fossils
From studying the 1975 book by Robert V. Kesling & Ruth B. Chilman: Strata and Megafossils of the Middle Devonian Silica Formation: Museum of Paleontology, Papers on Paleontology, No. 8, pg. 54, pl. 43, 45, I believe that the above fossils can be called Aulocystis auloporidea.