Plumatella fruticosa looks initially like F. sultana, but has horse shoe shaped polyps.
These pictures were taken in the 'Gat van Hulsebos' in Zuidlaren, the Netherlands.
The next picture shows a typical view of a colony. The split in two zooids at the end of a branch is often seen.
This colony has chosen a sub optimal habitat given the amount of silt collected on it.
The following cut-out shows how statoblasts form in the zooid body.
In another lake P. fruticosa grew between and underneath planks of a platform that is used for scuba training. Here a colony is shown living between two planks and surrounded by algae.
The next two photos show P. fruticosa growing on the side of a rock (part of a shore protection) and a cutout of the colony. The colony is only a few centimeters in size. Apologies for the dust in the photo. It does make more clear why the colony is growing on the side of the rock, rather than on top of it. Some particles are large enough to swamp a polyp.
In some of the zooids' branches statoblasts can be seen as light disks.
At the top right side a small colony Cristatella mucedo can be seen.
Between the branches of the colony a worm species is crawling (Stylaria lacustris; somewhat left and below of the middle). The balls that are scattered everywhere are not part of the P. fruticosa colony, but are a colony forming rotifer Synantherina socialis. At the very right side in the middle of the photo a small Hydra vulgaris is living.
The third photo shows the worm in more detail (picture taken under a microscope). I also found the same worm in Fredericella sultana colonies and on Cristatella mucedo colonies.
I wondered how the thin and brittle looking colonies stayed attached. The first impression is that they are connected at one point at the base of the colony stem. I searched my photo archive and found this cut out of another colony, growing on a submerged Christmas tree.
The colony forms creeping zooids across the substrate. Possibly these are anchored using some form of sticky substance. In some places it appears like the colony creates a 'foot' to improve attachment; for instance a bit above the small yellow blob at the underside of the branch, about 1/3 from the left side.
Finally another photo of a well developed and free hanging colony.