The first impression of P. articulata is a fine brownish bushy growth without a clear structure.
in this picture there is also an assel.

Specially if some sediment covers a colony it is easy to overlook a colony. They favor hidden locations and take to the fall to grow to significant size.

This picture of a young crawling colony show how beautiful the species is.

P. articulata seems to prefer to grow in this type of bushy colonies. This colony is partially covered in ciliates (small white dots). Also several colonies Synanthera socialis (radiates) can be seen as round shapes.

This picture was taken end of October and shows a P. articulata colony of significant size. As a comparison the bivalve on the picture are zebramussles of 2 to 3 cm.