A representative of the order Dendroidea, described as Graptolodendrum mutabile n.gen., n.sp., differs from other dendroid graptolites in its bithecae whose po sition is not stabilized. Mostly, they occur on one side of the stipe and,
rarely, on both sides alternatively which is a rule in the Dendroidea. Th e fusellar structure of autothecae, mostly irregular in the distal part, is also un stabilized. The position of the pore which pierces the wall of metasicula, as in the Graptoloidea, and not of prosicula, is a fully exceptional character in the representative of the Dendroidea. The material in vestigated has been etched ou t from the Middle Ordovician erratic boulders of Poland.