My Canadian correspondent confirms that the four seeds in every fruit appear
to be a regular feature. This would seem to preclude Lonicera which tends to
have a varying number of seeds per fruit.

Plants in Labiatae/Verbenaceae tend to have square stems or twigs. In this
case the twigs are round
PvR

Gene Newcomb schreef

Another thought. Could this be a very healthy Lonicera? The paired fruits
made me think of this and there are some woody, non-vining types with dark
colored fruits like _L. ledebourii_. In a park things may be pruned to
shapes that are not normal. A picture might help, or even more some
description of the flowers.

Gene Newcomb

Stewart Robert Hinsley wrote:

Stewart Robert Hinsley writes

Does something like _Callicarpa_ (Lamiaceae ex Verbenaceae, in Judd et
al) make sense? Some _Callicarpa_ have purple berries, but the one I
coincidentally saw today had mid-purple, rather than dark-purple,
berries. Judd et al have opposite-leaved foliage and drupes with 1-4
pits as traits which occur in both Verbenaceae and Lamiaceae.

I find that _Clerodendrum_ is also in this taxonomic region.
--
Stewart Robert Hinsley